SmarterEd

Aussie Maths & Science Teachers: Save your time with SmarterEd

Decimals, SM-Bank 026

Would 3.4 be approximately equal to 3 or 4 when rounded to the nearest whole number?  (1 mark)

Show Answers Only

`3`

Show Worked Solution

Method 1.

`text(Test 3:)\ 3.4-3 = 0.4`

`text(Test 4:)\ 4-3.4 = 0.6`

`:.\ 3.4 ~~ 3\ text{(nearest whole number) as it is closer}`
 
Method 2.

`text(Using a number line)`
 

`:.\ 3.4 ~~ 3\ text{(nearest whole number) as it is closer}`

Decimals, SM-Bank 025

Would 2.47 be approximately to 2.4 or 2.5 when rounded to 1 decimal place?  (1 mark)

Show Answers Only

`2.5`

Show Worked Solution

Method 1.

`text(Test 2.4:)\ 2.47-2.4 = 0.07`

`text(Test 2.5:)\ 2.5-2.47 = 0.03`

`:.\ 2.47 ~~ 2.5\ text{(1 d.p.) as it is closer}`
 
Method 2.

`text(Using a number line)`

`:.\ 2.47 ~~ 2.5\ text{(1 d.p.) as it is closer}`

Decimals, SM_Bank 024

John measured the water depth at the end of his jetty for five days in a row.

The measurements are summarised in the table below.

  Monday Tuesday Wednesday Thursday Friday
Water Level 1.24 m 1.07 m 1.42 m 1.15 m 1.38 m
  1. On which day was the water level the highest?  (1 mark)

  2. On which day was the water level the lowest?  (1 mark)

  3. On which day was the median (middle) water level measurement?  (1 mark)

  4. What is the difference between the highest and lowest water levels?  (2 marks)

Show Answers Only

a.    `text(Wednesday)`

b.    `text(Tuesday)`

c.    `text(Monday)`

d.    `0.35\ text(metres)`

Show Worked Solution

`text(Order from lowest to highest water level)`

`=>\ text(Tues , Thurs , Mon , Fri , Wed) `

a.    `text(Highest) = 1.42\ text(m) =>text(Wednesday)`

b.    `text(Lowest) = 1.07\ text(m) =>text(Tuesday)`

c.    `text(Middle) = 1.24\ text(m) =>text(Monday)`

d.    `text(Difference between highest and lowest)`

`=1.42-1.07`

`= 0.35\ text(metres)`

Decimals, SM-Bank 023

Arrange these decimal numbers in descending order.  (2 marks)

`10.045 , 10.04 , 10.450 , 10.145 , 10.405`

Show Answers Only

`10.450 , 10.405 , 10.145 , 10.045 , 10.04 `

Show Worked Solution

`text(Order from largest to smallest)`

`=> 10.450 , 10.405 , 10.145 , 10.045 , 10.04 `

Decimals, SM-Bank 021

Write each of the following mixed numbers as decimals.

  1. `5 3/10`  (1 mark)

  2. `10 2/100`  (1 mark)

  3. `1 32/1000`  (1 mark)

Show Answers Only

a.    `5.3`

b.    `10.02`

c.    `1.032`

Show Worked Solution

a.    `5 3/10 = 5.3`

b.    `10 2/100 = 10.02`

c.    `1 32/1000 = 1.032`

Decimals, SM-Bank 020

Write each of the following proper fractions as decimals.

  1. `4/10`   (1 mark)

  2. `77/100`   (1 mark)

  3. `9/100`   (1 mark)

  4. `395/1000`   (1 mark)

  5. `67/1000`   (1 mark)

Show Answers Only

a.    `0.4`

b.    `0.77`

c.    `0.09`

d.    `0.395`

e.    `0.067`

Show Worked Solution

a.    `4/10 = 0.4`

b.    `77/100 = 0.77`

c.    `9/100 = 0.09`

d.    `395/1000 = 0.395`

e.    `67/1000 = 0.067`

Decimals, SM-Bank 019

Vivian and Curtly throw a cricket ball from the boundary of the cricket oval to the wicket-keeper.

It takes Vivian's throw 3.48 seconds to reach the wicket-keeper.

It takes Curtly's throw 1.84 seconds.

What is the difference in the time taken to reach the wicket-keeper between the two throws?  (2 marks)

Show Answers Only

`1.64\ text(seconds)`

Show Worked Solution
`text(Time Difference)` `= 3.48-1.84`
  `= 3.48-2 + 0.16`
  `= 1.48 + 0.16`
  `= 1.64\ text(seconds)`

 
`:.\ text(The difference in the time taken is 1.64 seconds.)`

Decimals, SM_Bank 018

A hot air balloon is 25.2 metres high.

The length of the balloon section is 21.55 metres.
 

  
What is the height of the basket section?  (2 marks)

Show Answers Only

`text(3.65 metres)`

Show Worked Solution

`text(Let)\ \ h =\ text(height of basket section)`

`h + 21.55` `= 25.2`
`:. h` `= 25.2-21.55`
  `= 25.2-22 + 0.45`
  `= 3.2 + 0.45`
  `= 3.65`

`:.\ text(The basket section is 3.65 metres high)`

Fractions, SM-Bank 070

Write reciprocals for the following.

  1. `4/5`  (1 mark)

  2. `3`  (1 mark)

  3. `1 3/4`  (2 marks)

Show Answers Only

a.    `5/4`

b.    `1/3`

c.    `4/7`

Show Worked Solution
a.    `5/4`
 `=> 4/5\ \ \ \ text{(Swap the numerator and denominator)}`

 

b.    `3` `= 3/1\ \ \ \ text{(Write whole numbers as fractions with a denominator of 1)}`  
  `=> 1/3\ \ \ \ text{(Then swap the numerator and denominator)}`  

 

c.    `1 3/4`
 `= 7/4 \ \ \ \ text{(Change mixed numbers to improper fractions)}`
  `=> 4/7 \ \ \ \ text{(Then swap the numerator and denominator)}`

Decimals, SM-Bank 014 MC

Roger had tests to check his health that are summarised in the table below.

Test Normal range Roger's result
Resting heart rate 60 to 95 92
Blood sugar 4.2 to 6.1 4.1
Vitamin C 0.4 to 1.7 0.5

For which tests were Roger's results within the normal range?

  1. Resting heart rate and blood sugar
  2. Blood sugar and vitamin C only
  3. Resting heart rate only
  4. Resting heart rate and vitamin C only
Show Answers Only

`D`

Show Worked Solution

`text(Checking each test:)`

`text(Resting heart rate → 92 is within 60 and 95)`

`text(Blood sugar → 4.1 is not within 4.2 and 6.1 )`

`text(Vitamin C → 0.5 is within 0.4 and 1.7)`

`:.\ text(Resting heart rate and vitamin C only)`

`text(are within the normal range.)`

`=> D`

Decimals, SM-Bank 002 MC

India recorded the results of a 400 metres running race final in the table below.

Ist Place 52.26 seconds
2nd Place 52.62 seconds
3rd Place ?
4th Place 53.19 seconds

The time of the runner who came in 3rd place could be

  1. `text(52.57 seconds.)`
  2. `text(52.71 seconds.)`
  3. `text(53.21 seconds.)`
  4. `text(53.94 seconds.)`
Show Answers Only

`B`

Show Worked Solution

`text{Eliminate A as it lies between 1st and 2nd place.}`

`text{Eliminate C and D as both are larger than 4th place.}`

`text{52.71 is slower than 2nd place (52.62) but faster than 4th place (53.19).}`

`=> B`

Decimals, SM-Bank 004 MC

Kelly measures the length of fish she catches for her research.

A. B. C. D.

  
Which fish has a length closest to 25 cm?

Show Answers Only

`A`

Show Worked Solution

`text(Difference of each option:)`

`25.14-25` `= 0.14\ text(cm)`
`25-24.8` `= 0.20\ text(cm)`
`25-24.76` `= 0.24\ text(cm)`
`25.3-25` `= 0.30\ text(cm)`

 
`:. 25.14\ text(cm is closest.)`

`=> A`

Decimals, SM-Bank 006

Richard is a runner.

The length of his last 4 half marathon distances are recorded in the table below.

Half marathon Distance (km)
1 21.1
2 20.35
3 20.295
4 22.095

Which half marathon had the shortest distance?  (1 mark)

Show Answers Only

`text(Half marathon 3)`

Show Worked Solution

`20.295\ text(is the shortest distance.)`

`:.\ text(Half marathon 3 was the shortest.)`

Decimals, SM-Bank 007 MC

Connie is reading the outside temperature during winter in her hometown.

What is the value of the point marked  `text(P)`  on this temperature scale?
 
 

  1. `-3.4^@text(C)`
  2. `-3.8^@text(C)`
  3. `-2.1^@text(C)`
  4. `-2.2^@text(C)`
Show Answers Only

`D`

Show Worked Solution
`text(Each increment)` `= 0.2^@text(C)`
`:.\ text(Value of  P)` `= -2 + (- 0.2)`
  `= -2.2^@text(C)`

`=> D`

Decimals, SM-Bank 010 MC

Which of these numbers has a 3 in the thousandths place?

  1. 0.3244
  2. 2.8309
  3. 7.8231
  4. 23 082.8915
Show Answers Only

`C`

Show Worked Solution

`text{The digits to the right of the decimal place are (in order):}`

`text(tenths, hundredths, thousandths, …)`

`:.\ text(The correct number is 7.8231)`

`=> C`

Decimals, SM_Bank 012

The average cost of manufacturing a car tyre is calculated in dollars, and shown below.
 

What is the average cost rounded to the nearest 5 cents?  (1 mark)

Show Answers Only

`$17.95`

Show Worked Solution
`text(Average Cost)` `= $17.943701`
  `= 17.94\ text{(2 decimal places)}`
  `~~ $17.95\ text{(nearest 5 cents)}`

Fractions, SM-Bank 061

Transmission Oils import engine oil.

They sell one brand of engine oil at `2 1/4` times the wholesale price.

If the wholesale price is $12 per litre, what is the selling price per litre?  (2 marks)

Show Answers Only

`$27\ text(per litre)`

Show Worked Solution

`text(Wholesale price) = $12\ text(per litre)`

`text(Sale price)` `= 2 1/4 xx 12`
  `= 9/4 xx 12`
  `= 9 xx 3`
  `=27`

 
`:.\ text(The selling price per litre)\ = $27`

Fractions, SM-Bank 059

Find:

  1. `1/4` of 20 apples.  (1 mark)

  2. `4/5` of 60 years.  (1 mark)

  3. `3/11` of 110 kilometres.  (1 mark)

Show Answers Only

a.    `5\ text(apples)`

b.    `48\ text(years)`

c.    `30\ text(kilometres)`

Show Worked Solution

a.    `1/4 xx 20 =1/4 xx 20/1= 5\ text(apples)`
 

b.    `4/5 xx 60`
`=4/5 xx 60/1`  
  `=4 xx 12`  
  `= 48\ text(years)`  

   

c.    `3/11 xx 110`
`=3/11 xx 110/1`
  `=3 xx 10`
  `= 30\ text(kilometres)`

 

Fractions, SM-Bank 058

Evaluate the following number sentences, giving your answers in simplest form.

  1. `2 3/7-1 2/7`  (1 mark)

  2. `3 1/2-1 3/5`  (2 marks)

  3. `4 1/4-3 1/2`  (2 marks)

Show Answers Only

a.    `1 1/7`

b.    `1 9/10`

c.    `3/4`

Show Worked Solution
a.    `2 3/7-1 2/7` `=1 3/7 -2/7`
  `= 1 1/7`

 

b.    `3 1/2-1 3/5` `=3 5/10-1 6/10`
  `= 2 5/10-6/10`
  `=1 9/10`

 

c.    `4 1/4-3 1/2` `=1 1/4-1/2`
  `= 1 1/4-2/4`
  `=3/4`

Fractions, SM-Bank 057 MC

Mallory has  `3/8`  cup of raisins.

She needs  `3/4`  cup of raisins for a fruit cake she is making.

How many more cups of raisins does Mallory need for the recipe?

  1. `1/8\ text(cup)`
  2. `1/4\ text(cup)`
  3. `3/8\ text(cup)`
  4. `1/2\ text(cup)`
Show Answers Only

`C`

Show Worked Solution
`text(Raisins needed)` `= 3/4-3/8`
  `=6/8-3/8`
  ` =3/8\ text(cup)`

 
`=> C`

Fractions, SM-Bank 056

Sally makes bird feeders to hang in her garden.

The table below shows the fraction of the bird feeder eaten each day by the birds. 

\begin{array} {|l|c|c|}
\hline \textbf{Day} & \textbf{Fraction Eaten} \\
\hline \text{Monday}  &  3/10\\
\hline \text{Tuesday} & 1/5  \\
\hline \text{Wednesday} &  1/4  \\
\hline \text{Thursday} & ?   \\
\hline \end{array}

  1. If the whole feeder was consumed in four days, what fraction did the birds eat on Thursday?  (2 marks)

  2. The bird feeder weighs 5 kilograms. How many kilograms were consumed on Monday?  (2 marks)

Show Answers Only

a.    `1/4`

b.    `1 1/2\ text(kilograms)`

Show Worked Solution
a.    `text(Eaten Thursday)` `= 1-(3/10+1/5+1/4)`
  `= 1-(6/20+4/20+5/20)`
  `= 1-15/20`
  `=5/20=1/4`

 

b.    `text(Monday Kilograms)` `= 3/10 xx 5`
  `= 15/10`
  `= 1 1/2\ text(kilograms)`

Fractions, SM-Bank 055

Evaluate the following number sentences, giving your answers in simplest form.

  1. `1/6-5/6`  (1 mark)

  2. `4/9-1/2`  (2 marks)

  3. `-3/4-1/2`  (2 marks)

Show Answers Only

a.    `-2/3`

b.    `-1/18`

c.    `-1 1/4`

Show Worked Solution
a.    `1/6-5/6` `=-4/6`
  `= -2/3`

 

b.    `4/9-1/2` `=(4 xx 2)/(9 xx 2)-(1 xx 9)/(2 xx 9)`
  `= 8/18-9/18`
  `=-1/18`

 

c.    `-3/4-1/2` `=-3/4-2/4`
  `= -5/4`
  `=-1 1/4`

Fractions, SM-Bank 054

Evaluate the following number sentences, giving your answers in simplest form.

  1. `7/12-1/4`  (1 mark)

  2. `3/5-2/7`  (2 marks)

  3. `1/2-4/9`  (2 marks)

Show Answers Only

a.    `1/3`

b.    `11/35`

c.    `1/18`

Show Worked Solution
a.    `7/12-1/4` `=7/12- (1 xx 3)/(4 xx 3)`
  `= 7/12-3/12`
  `=1/3`

 

b.    `3/5-2/7` `=(3 xx 7)/(5 xx 7)- (2 xx 5)/(7 xx 5)`
  `= 21/35-10/35`
  `=11/35`

 

c.    `1/2-4/9` `=(1 xx 9)/(2 xx 9)- (4 xx 2)/(9 xx 2)`
  `= 9/18-8/18`
  `=1/18`

Fractions, SM-Bank 047

Mike is downloading a complete hard drive onto his new computer.

It should take 24 minutes to download the full hard drive.

Mike loses his internet connection when  `5/6`  of the hard drive is downloaded.

How many more minutes are needed for Mike to complete the download?  (2 marks)

Show Answers Only

`text(4 minutes)`

Show Worked Solution

`5/6 xx 24 =\ text(20 minutes)`

`:.\ text(Minutes needed)` `= 24-20`
  `= 4\ text(minutes)`

Fractions, SM-Bank 044

Add the following mixed numbers giving your answer in simplest form.

  1. `2 5/8 + 1 3/4`  (2 mark)

  2. `4 5/6 + 3 4/9`  (2 mark)

  3. `1 3/5 + 5 2/3 + 4 7/10` (2 marks)

Show Answers Only

a.    `4 3/8`

b.    `8 5/18`

c.    `11 29/30`

Show Worked Solution

a.    Method: Adding whole number parts first

  `2 5/8+1 3/4` `=2 + 1 + 5/8 + 3/4\ \ \ text(LCD)\= 8`
    `= 3 + 5/8 + 6/8`
    ` = 3 + 11/8 = 4 3/8`

    
b.    Method: Adding whole number parts first

  `4 5/6 +3 4/9` `=4 + 3 + 5/6 + 4/9\ \ \ text(LCD)\= 18`
    `= 7 + (5 xx 3)/(6 xx 3) + (4 xx 2)/(9 xx 2)`
    ` = 7 + 15/18 + 8/18`
    `= 7 + 23/18 = 8 5/18`

  
c.    Method: Adding whole number parts first

  `1 3/5+5 2/3+4 7/10` `=1 + 5 + 4 +3/5 +2/3+7/10\ \ \ text(LCD)\= 30`
    `= 10 + (3 xx 6)/(5 xx 6) + (2 xx 10)/(3 xx 10) + (7 xx 3)/(10 xx 3)`
    ` = 10 + 18/30 + 20/30 + 21/30`
    `= 10 + 59/30 = 11 29/30`

Fractions, SM-Bank 043

Add the following mixed numbers giving your answer in simplest form.

  1. `1 1/3 + 1 2/3`  (1 mark)

  2. `2 4/9 + 1 2/9`  (2 mark)

  3. `1 1/11 + 2 5/11 + 4 7/11` (2 marks)

Show Answers Only

a.    `3`

b.    `3 2/3`

c.    `8 2/11`

Show Worked Solution

a.    Method 1: Adding whole number parts first

  `1 1/3+1 2/3` `=1 + 1 +1/3 + 2/3`
    `= 2 + 3/3`
    ` = 3`

Method 2: Changing to improper fractions

  `1 1/3+1 2/3` `=(3 xx 1 + 1)/3 + (3 xx 1 + 2)/3`
    `= 4/3 + 5/3`
    ` = 9/3 = 3`

 
b.    Method 1: Adding whole number parts first

  `2 4/9 +1 2/9` `=2 + 1 +4/9 + 2/9`
    `= 3 + 6/9`
    ` = 3 2/3`

Method 2: Changing to improper fractions

  `2 4/9 +1 2/9` `=(2  xx 9 + 4)/9 + (1 xx 9 + 2)/9`
    `= 22/9 + 11/9`
    ` = 33/9 `
    `= 3 6/9 = 3 2/3`

 
c.    Method 1: Adding whole number parts first

  `1 1/11+2 5/11+4 7/11` `=1 + 2 + 4 +1/11 +5/11+7/11`
    `= 7 + 13/11`
    ` = 8 2/11`

Method 2: Changing to improper fractions

  `1 1/11+2 5/11+4 7/11` `=(1 xx 11 + 1)/11 +(2 xx 11 + 5)/11 + (4 xx 11 + 7)/11 +`
    `= 12/11 + 27/11+51/11`
    ` = 90/11 = 8 2/11`

 

Fractions, SM-Bank 042

Add the following fractions giving your answer in simplest form.

  1. `1/3 + 1/4`  (1 mark)

  2. `3/10 + 1/5`  (2 mark)

  3. `1/2 + 1/3 + 1/8` (2 marks)

Show Answers Only

a.    `7/12`

b.    `1/2`

c.    `23/24`

Show Worked Solution
a.     `1/3+1/4` `= (1xx4)/(3 xx 4) + (1 xx 3)/(4 xx 3)\ \ \ text(LCD)\= 12`
    `= 4/12 + 3/12`
    ` = 7/12`

 

b.     `3/10 +1/5` `= 3/10 + (1 xx 2)/(5 xx 2)\ \ \ text(LCD)\= 10`
    `= 3/10 + 2/10`
    ` = 5/10 = 1/2`

 

c.     `1/2 +1/3 + 1/8` `= (1 xx 12)/(2 xx 12) + (1 xx 8)/(3 xx 8) + (1 xx 3)/(8 xx 3)\ \ \ text(LCD)\= 24`
    `= 12/24 + 8/24 + 3/24`
    ` = 23/24`

Fractions, SM-Bank 041

Add the following fractions giving your answer as a mixed number where necessary.

  1. `4/9 + 1/9`  (1 mark)

  2. `5/7 + 6/7`  (1 mark)

  3. `2/15 + 7/15 + 8/15` (2 marks)

Show Answers Only

a.    `5/9`

b.    `1 4/7`

c.    `1 2/15`

Show Worked Solution

a.    `4/9 + 1/9 = 5/9`

b.    `5/7 + 6/7 = 11/7 = 1 4/7`

c.    `2/15 + 7/15 + 8/15 = 17/15 = 1 2/15`

Fractions, SM-Bank 040

Three friends are baking cupcakes for the Spring Fair.

Maryanne will bake `1/4` of the cupcakes, Martin has a large oven and will bake `2/3` of the cupcakes and Monty will bake the rest.

What fraction of the cupcake baking does Monty complete?  (2 marks)

Show Answers Only

`1/12`

Show Worked Solution

`text(Monty’s Baking)`

`= 1-(1/4 + 2/3)\ \ text(LCD)\= 12`

`= (1xx12)/(1 xx 12)-((1xx3)/(4 xx 3) + (2 xx 4)/(3 xx 4))`

`= 12/12-(3/12 + 8/12)`

`= 12/12-11/12 = 1/12`

`:.\ text(Monty bakes)\ 1/12\ text(of the cupcakes)`

Fractions, SM-Bank 039

Three friends are running as a team in a fun run.

Thanh hopes to finish `3/7` of the run, Jamieson is confident he can complete `1/2` of the run and Jules will complete the rest.

What fraction of the fun run does Jules complete?  (2 marks)

Show Answers Only

`1/14`

Show Worked Solution

`text(Jules)`

`= 1-(3/7 + 1/2)\ \ text(LCD)\= 14`

`= (1xx14)/(1 xx 14)-((3xx2)/(7 xx 2) + (1 xx 7)/(2 xx 7))`

`= 14/14-(6/14 + 7/14)`

`= 14/14-13/14 = 1/14`

`:.\ text(Jules completes)\ 1/14\ text(of the race)`

Fractions, SM_Bank 038

What is the lowest common denomiator of the following sets of fractions?

  1. `1/4, 1/8`   (1 mark)

  2. `2/3, 4/5`   (1 mark)

  3. `1/2, 2/3, 1/6`   (1 mark)

  4. `1/9, 5/6, 7/12`   (1 mark)
Show Answers Only

a.    `8`

b.    `15`

c.    `6`

d.    `36`

Show Worked Solution

a.    `text(8 is the lowest number that is a multiple of both 4 and 8)`

`:.\ text(LCD) (1/4, 1/8) = 8`
 

b.    `text(15 is the lowest number that is a multiple of both 3 and 5)`

`:.\ text(LCD) (2/3, 4/5)= 15`  
  

c.   `text(6 is the lowest number that is a multiple of 2, 3 and 6)`

`:.\ text(LCD) (1/2, 2/3, 1/6) = 6` 
   

d.    `text(36 is the lowest number that is a multiple of 9, 6 and 12)`

`:.\ text(LCD) (1/9, 5/6, 7/12) = 36`  

Fractions, SM-Bank 037

What is the lowest common multiple of the following sets of numbers?

  1. `2, 5`  (1 mark)

  2. `3, 9`  (1 mark)

  3. `2, 3, 6`  (1 mark)

  4. `4, 6, 8`  (1 mark)
Show Answers Only

a.    `10`

b.    `9`

c.    `6`

d.    `24`

Show Worked Solution

a.    `text(Multiples of 2:)\ 2, 4, 6, 8, 10`

`text(Multiples of 5:)\ 5, 10`

`:.\ text(LCM (2, 5))= 10`  
 

b.    `text(Multiples of 3:)\ 3, 6, 9`

`text(Multiples of 9:)\ 9`

`:.\ text(LCM (3, 9))= 9`  
  

c.   `text(Multiples of 2:)\ 2, 4, 6`

`text(Multiples of 3:)\ 3, 6`

`text(Multiples of 6:)\ 6`

`:.\ text(LCM (2, 3, 6))= 6`  
   

d.    `text(Multiples of 4:)\  4, 8, 12, 16, 20, 24`

`text(Multiples of 6:)\ 6, 12, 18, 24`

`text(Multiples of 8:)\ 8, 16, 24`

`:.\ text(LCM (4, 6, 8))= 24`  

Fractions, SM-Bank 036

Jaime and Jordan ordered 2 extra large pizzas for dinner.

Jaime ate `2/5` of an extra large pizza.

  1. If Jordan ate 3 times as much pizza as Jaime, how much pizza did Jordan eat? Give your answer as a mixed number.  (1 mark)

  2. What fraction of pizza is left over?  (2 marks)

Show Answers Only

a.    `1 1/5\ text(pizzas)`

b.    `2/5\ text(of a pizza)`

Show Worked Solution

a.    `text(Jordan’s Pizza)`

`= 3 xx 2/5`

`= 6/5`

 `= 1 1/5\ text(pizzas)`
  

b.    `text(Leftover pizza)`

`= 2-(2/5 + 1 1/5)`

`= 2-1 3/5`

`= 2/5\ text(of a pizza)`