An unknown number is added to `2`.
The result is multiplied by `4` to give an answer of `-4`.
Which of these is the unknown number?
- `2`
- `1`
- `-1`
- `-3`
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An unknown number is added to `2`.
The result is multiplied by `4` to give an answer of `-4`.
Which of these is the unknown number?
`D`
`text(Option D:)`
`text(If unknown number) = -3`
` -3 + 2 = -1`
`-1 × 4 = -4\ text((correct))`
`=> D`
An unknown number is added to `5`.
The result is multiplied by `3` to give an answer of `-6`.
Which of these is the unknown number?
`A`
`text(Option A:)`
`text(If unknown number) = -7`
` -7 + 5 = -2`
`-2 × 3 = -6\ text((correct))`
`=> A`
Complete the following table. (3 marks)
\begin{array} {|c|c|c|c|}
\hline × & \ \ 3\ \ & -4 & -2 \\
\hline -1 & & \\
\hline 5 & & \\
\hline \end{array}
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\begin{array} {|c|c|c|c|}
\hline × & \ \ 3\ \ & -4 & -2 \\
\hline -1 & -3 & 4 & 2 \\
\hline 5 & 15 & -20 & -10 \\
\hline \end{array}
\begin{array} {|c|c|c|c|}
\hline × & \ \ 3\ \ & -4 & -2 \\
\hline -1 & -3 & 4 & 2 \\
\hline 5 & 15 & -20 & -10 \\
\hline \end{array}
Complete the following table. (3 marks)
\begin{array} {|c|c|c|c|}
\hline + & \ \ 4\ \ & -5 & -3 \\
\hline -2 & & \\
\hline 7 & & \\
\hline -10 & & \\
\hline \end{array}
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\begin{array} {|c|c|c|c|}
\hline + & \ \ 4\ \ & -5 & -3 \\
\hline -2 & 2 & -7 & -5 \\
\hline 7 & 11 & 2 & 4 \\
\hline -10 & -6 & -15 & -13 \\
\hline \end{array}
\begin{array} {|c|c|c|c|}
\hline + & \ \ 4\ \ & -5 & -3 \\
\hline -2 & 2 & -7 & -5 \\
\hline 7 & 11 & 2 & 4 \\
\hline -10 & -6 & -15 & -13 \\
\hline \end{array}
Find the values of the following. (3 marks)
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a. `11` b. `2` c. `-5`
`text(Remember:)\ − − = +`
a. `4-(-7)= 4 + 7 = 11`
b. `-1-(-3) = -1 + 3 = 2`
c. `-21-(-16) = -21 + 16 = -5`
Evaluate the following. (3 marks)
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a. `-3` b. `-11` c. `-15`
a. `5-8 = -3`
b. `-7-4 = -11`
c. `-7-6-2 = -15`
Evaluate the following. (3 marks)
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a. `7` b. `-3` c. `-4`
a. `15 + (-8) = 15-8 = 7`
b. `-7 + 4 = -3`
c. `-7 + 5 + (-2) = -7 + 5-2 = -4`
Evaluate the following. (3 marks)
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a. `-6` b. `-7` c. `0`
a. `-1 + (-5) = -1-5 = -6`
b. `-12 + 5 = -7`
c. `-3 + 4 + (-1) = -3 + 4-1 = 0`
Jennifer opened a bank account with $500. Each week for 4 weeks she withdrew $122 for rent. At the end of the month the bank deducted $15 in fees.
What was the balance of Jennifer's bank account at the end of the month? (2 marks)
`-$3`
`text(Balance)\ = 500-122 xx 4-15 = 500-488-15 = -3`
`:.\ text(Jennifer’s balance)\ = -$3`
Morgan had $134 in his bank account. At the end of March he paid $132 car insurance and the bank deducted $10 in fees.
What was the balance of Morgan's bank account at the beginning of April? (2 marks)
`-$8`
`text(Balance)\ = 134-132-10 = -8`
`:.\ text(Morgan’s balance)\ = -$8`
Jasper is a meteorologist working in Antartica. One of his jobs each week is to upload the daily maximum and minimum temperatures to the Base Camp website.
Jasper has partially completed his log book for this week but will need his additional notes to fill in the missing entries before he can upload them to the website.
Using Jasper's notes below, complete the missing log book entries. (4 marks)
Jasper's Additional Notes:
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TEMPERATURE LOG BOOK
\begin{array} {|l|c|c|}
\hline \textbf{Day} & \textbf{Minimum} & \textbf{Maximum} \\
\hline \text{Monday} & -10° & -1° \\
\hline \text{Tuesday} & -15° & \colorbox{lightblue}{−4°} \\
\hline \text{Wednesday} & -7° & -2° \\
\hline \text{Thursday} & \colorbox{lightblue}{−20°} & -8° \\
\hline \text{Friday} & -17° & -6° \\
\hline \text{Saturday} & \colorbox{lightblue}{−21°} & \colorbox{lightblue}{−2°} \\
\hline \text{Sunday} & -19° & -4° \\
\hline \end{array}
`1.\ text{Tuesday’s Maximum}\= -1-3 = -4`
`2.\ text{Thursday’s Minimum}\= -8-12 = -20`
`3.\ text{Saturday’s minimum}\= 3 xx -7 = -21`
`4.\ text{Saturday’s maximum}\= -4 ÷ 2 = -2`
TEMPERATURE LOG BOOK
\begin{array} {|l|c|c|}
\hline \textbf{Day} & \textbf{Minimum} & \textbf{Maximum} \\
\hline \text{Monday} & -10° & -1° \\
\hline \text{Tuesday} & -15° & \colorbox{lightblue}{−4°} \\
\hline \text{Wednesday} & -7° & -2° \\
\hline \text{Thursday} & \colorbox{lightblue}{−20°} & -8° \\
\hline \text{Friday} & -17° & -6° \\
\hline \text{Saturday} & \colorbox{lightblue}{−21°} & \colorbox{lightblue}{−2°} \\
\hline \text{Sunday} & -19° & -4° \\
\hline \end{array}
James runs a tyre fitting company.
At the beginning of February he took out a `$50\ 000` bank loan to expand his workshop.
In July James had flood damage in his workshop and added `$20\ 000` to his bank loan to pay for repairs.
By the end September he had made loan repayments totalling `$12\ 000` and had also deposited business profits of `$15\ 000` into his loan account.
Write a number sentence and use it to calculate how much James owed at the end of September. (3 marks)
`-$43\ 000`
| `text(Amount of debt)` | `= -50\ 000-20\ 000+12\ 000+15\ 000` | |
| `= -70\ 000+27\ 000 ` | ||
| `= -43\ 000` |
`:.\ text(James’ debt at the end of September)\= -$43\ 000`
Use the number line below to show that `-3-(-9) = 6`. (2 marks)
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Use the number line below to show that `5+(-8) = -3`. (2 marks)
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The daily high and low temperatures are measured in four ski resorts and recorded in the table below.
\begin{array} {|l|c|c|}
\hline \textbf{Ski Resort} & \textbf{Low} & \textbf{High} \\
\hline \text{Thredbo} & -1° & 6° \\
\hline \text{Charlotte's Pass} & -5° & 1° \\
\hline \text{Mount Hotham} & -2° & 3° \\
\hline \text{Perisher} & -4° & 4° \\
\hline \end{array}
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a. `text(Mount Hotham)`
b. `text(Charlotte’s Pass)`
`text(Considering all options.)`
| `text(Thredbo)` | `=6-(-1)` | `=7` |
| `text(Charlotte’s Pass)` | `=1-(-5)` | `=6` |
| `text(Mount Hotham)` | `=3-(-2)` | `=5` |
| `text(Perisher)` | `=4-(-4)` | `=8` |
a. `text(Lowest Range)\ =\text(Mount Hotham)`
b. `text(Range of)\ 6 = text(Charlotte’s Pass)`
At midday the temperature is `-`3°C.
At 9pm the temperature is `-`12°C.
Which one of these calculations can be used to work out how many degrees warmer it is at midday than at 9 pm?
`B`
| `text(Degrees warmer)` | `= -3-(-12)` | |
| `=-3 + 12` |
`=> B`
At midday the temperature is 10°C.
At sunset the temperature is `-`6°C.
Which one of these calculations can be used to work out how many degrees warmer it is at midday than at sunset?
`C`
| `text(Degrees warmer)` | `= 10-(-6)` | |
| `=10+6` |
`=> C`
Lindy is using a number line to show a pattern.
What are the next two numbers in Lindy’s pattern? (2 marks)
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`-7\ text(and) -4`
`text(The numbers are increasing by 3 each time.)`
`text(The first number is: )-10+3 =-7`
`text(and the second number is: )-7+3 = -4`
`:.\ -7\ text(and) -4\ text(are the next 2 numbers)`
Trad is using a number line to show a pattern.
What are the next two numbers in Trad’s pattern? (2 marks)
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`-6\ text(and) -11`
`text(The numbers are decreasing by 5 each time.)`
`text(The first number is: )-1-5 = -6`
`text(and the second number is: )-6-5 = -11`
`:.\ -6\ text(and) -11\ text(are the next 2 numbers)`
A buoy is in the ocean recording the height of waves passing by.
At sea level it measures 0 metres. It moves above and below sea level.
Which list gives four sea level recordings arranged in order from lowest to highest?
`D`
`=> D`
Two numbers added together equal 2.
The two numbers multiplied together equal −24.
What are the two numbers? (2 marks)
`6 and −4`
| `6 + -4` | `= 2` |
| `6 xx -4` | `= -24` |
`:. 6 and -4`
Which symbol `( <, = , >)` makes the number sentence correct? (1 mark)
| `2 - (4 + 3)` | |
`3 + 1 - 8` |
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`<`
| `2\-\(4 + 3)` | `<3 + 1\-\8` |
| `2\-\7` | `<4\-\8` |
| `\-\5` | `<\-\4` |
What is the value of the expression `3 + (-13) - (-6)`? (2 marks)
`-4`
| `3+(-13) – (-6)` | `= -10 + 6` |
| `= -4` |
Rachel lives in Broome where the temperature on a particular day was 46°C.
Rachel's son lives in Winnipeg, Canada, and on the same day the temperature there was −16°C.
What was the temperature difference between the two towns on this day? (2 marks)
`62°text(C)`
| `text(Temperature difference)` | `= 46-(-16)` |
| `= 62°text(C)` |
Which of the following changes is the smallest?
`B`
`text(Consider each option:)`
| `-8\ text(to)\ -4` | `=\ text(4° change)` |
| `-5\ text(to)\ -2` | `=\ text(3° change)` |
| `-2\ text(to)\ 3` | `=\ text(5° change)` |
| `3\ text(to)\ 7` | `=\ text(4° change)` |
`:.\ -5^@\ text(C to)\-2^@text(C is the smallest change.)`
`=> B`
Death Valley is the lowest point in the United States at `-`85 metres, which is below sea level.
King's Peak, also in the United States, is 4128 metres above sea level.
What is the difference, in metres, between Death Valley and King's Peak? (2 marks)
`4213\ text(metres)`
| `text(Difference)` | `= 4128- (-85)` |
| `= 4213\ text(metres)` |
Dilbert and Smacka were playing a game where they both started with zero points.
Dilbert's final score was 165 points and Smacka's final score was `-90`.
How many more points did Dilbert have than Smacka?
`D`
| `text(Difference)` | `= 165 – (-90)` |
| `= 255` |
`=> D`
Murray lives in Bundaberg, QLD, where the temperature on a particular day was 39°C.
Murray's son lives in Salt Lake City, USA, and on the same day the temperature there was `-`15°C.
What was the temperature difference between the two towns on this day? (2 marks)
`54°text(C)`
| `text(Temperature difference)` | `= 39-(-15)` |
| `= 54°text(C)` |
Manou placed an apple pie into his oven.
The 1st measurement of the apple pie's temperature was `-` 4°C.
Twenty minutes later, a second temperature reading was taken, which measured 21°C.
What was the change in temperature between the two measurements?
`C`
| `text(Change in temperature)` | `=21-(-4)` |
| `=25^@ text(C)` |
`:.\ text(An increase of 25°C.)`
`=> C`
The temperature at the summit of a large mountain is `-`6°C.
The temperature at the base of the mountain is 32°C warmer than at the summit.
What is the temperature at the base of the mountain? (2 marks)
`26^@text(C)`
`text(Temperature at the base of the mountain)`
`= -6 + 32`
`=26^@ text(C)`
Pen wrote the following number sequence.
`4, 2, 0, \-\2, \-\4`
What are the next four numbers in Pen's number sequence? (2 marks)
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`\-\6, \-\8, \-\10, \-\12`
`text(The numbers are decreasing by 2 each time.)`
`:.\ text(The next four numbers are: )\-\6, \-\8, \-\10, \-\12`
Two arrows point to numbers on a number line.
Which one of these numbers lies between the two arrows?
`A`
`text(Arrows are at approximately)\ \-\87\ text(and)\ \-\94`
`:.\ text(Number lies between)\ \-\87\ text(and)\ \-\94`
`:.\-\89`
`=> A`
Two arrows point to numbers on a number line.
Which one of these numbers lies between the two arrows?
`D`
`text(Arrows are at approximately)\ \-\34\ text(and)\ \-\27`
`:.\ text(Number lies between)\ \-\27\ text(and)\ \-\34`
`:.\-\33`
`=> D`
Ivan left home and turned off the heater.
Before turning off the heater, the temperature in the room was 25°C.
When Ivan arrived home from work that night, the temperature in the room was `\-\`2°C.
What was the change in temperature in the room? Write your answer as a directed number. (2 marks)
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`-27text(°C)`
Karen arrived home and turned on the heater.
Before turning on the heater, the temperature in the room was −5°C.
After fifteen minutes, the temperature in the room was 12°C.
What was the change in temperature in the room? Write your answer as a directed number. (2 marks)
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`\+\17\text(°C)`
The Nevis Bungy in Queenstown is the highest bungee jump in New Zealand.
Jumpers launch downwards from a platform and take just 8.5 seconds to freefall 134 metres before the bungee cord retracts for the first time.
Express the length of the freefall as a directed number. Consider the platform to be at zero length. (1 mark)
`-134\ text(metres)`
`134\ text(metres below the platform) = -134\ text(metres)`
The average temperature at the Mount Everest base camp in Tibet is 17 degrees below zero.
Write this temperature as a directed number. (1 mark)
`-17 \ º`
`17 \ text(degrees below zero) = -17\ º`
Most commercial jet planes gain their cruising altitude of approximately 8000 metres within 10 minutes after take off.
Write this height as a directed number. (1 mark)
`\+\8000\ text(metres)`
`text(Ground level) = 0\ text(metres)`
`:. 8000\ text(metres cruising altitude) = \+\8000\ text(metres)`
The operating depth of most modern submarines is approximately 375 metres below sea level.
Write this depth as a directed number. (1 mark)
`-375\ text(metres)`
`text(Sea level) = 0\ text(metres)`
`:. 375\ text(metres below sea level) = -375\ text(metres)`
Pixie enters the elevator in her high rise office building on level 5.
She travels down in the lift for 8 floors.
By considering the floors above ground level to be positive and the floors below ground level to be negative, write and solve a number sentence that gives Pixie's position in the building when she gets out of the elevator. (2 marks)
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`5 \-\8 = \-\3`
`text(Pixie enters at level 5 and descends 8 floors, therefore the number sentence is:`
`5 \-\8= \-\3`
Jerome is on holidays in Thredbo. His family is hoping for a good covering of snow as they are having snowboarding lessons.
Which of the following outside temperatures would produce the snow they need?
`D`
`text(The temperature must be below 0º C for snow to fall.)`
`text(Therefore, the outside temperature would need to be −15ºC.)`
`=> D`
The following data represents the ages of people on a riverboat cruise in Europe.
28, 35, 39, 39, 28, 34, 40, 43, 51, 34, 35, 39, 40, 46, 60
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a.
\begin{array} {r|lll} \textbf{Stem} & \textbf{Leaf} \\ \hline 2 & 8\ 8 \\ 3 & 4\ 4\ 5\ 5 \ 9\ 9\ 9\ \\ 4 & 0\ 0\ 3\ 6 \\ 5 & 1 \\ 6 & 0 \\ \end{array}
b. `39`
c. `39`
d. `text(Skewed)`
a. `text(Ordered data:) \ 28, 28, 34, 34, 35, 35, 39, 39, 39, 40, 40, 43, 46, 51, 60`
\begin{array} {r|lll} \textbf{Stem} & \textbf{Leaf} \\ \hline 2 & 8\ 8 \\ 3 & 4\ 4\ 5\ 5 \ 9\ 9\ 9\ \\ 4 & 0\ 0\ 3\ 6 \\ 5 & 1 \\ 6 & 0 \\ \end{array}
b. `text(Median)\ = \text(8th score)\ =\ 39`
c. `text(Mode)\ = \ 39`
d. `text(The data is skewed.)`
Which of the following terms best describes this distribution?
`B`
`text(The distribution has mean < median < mode.)`
`text(Therefore, the distribution is best described as negatively skewed.)`
`=>B`
Which of the following terms best describes this distribution?
`A`
`text(The distribution has mode < median < mean, therefore, the distribution is best described as positively skewed.`
`=>A`
Which of the following terms best describes this distribution?
`C`
`text(The distribution has mean = mode = median, therefore, the distribution is best described as symmetrical.`
`=>C`
Jason recorded the following marks out of 100 in his last 8 class tests.
74, 65, 70, 72, 95, 68, 70, 64
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a. `95`
b. `72.25 \-\69 = 3.25\ text(marks)`
c. “
a. `text(The test mark of 95 is significantly different from the other marks)`
`:.\ 95\ text(is an outlier)`
b. `text(Initial Mean)`
| `text(Mean)` | `=(74 + 65 + 70 + 72 + 95 + 68 + 70 + 64)/8` | |
| `= 578/8` | ||
| `= 72.25` |
`text(Mean without outlier)`
| `text(New Mean)` | `=(74 + 65 + 70 + 72 + 68 + 70 + 64)/7` |
| `= 483/7` | |
| `= 69` |
`:.\ text(The mean decreases by)\ 3.25\ text(marks)`
c. `text(Ordered marks):\ 64, \ 65, \ 68, \ 70, \ 70, \ 72, \ 74, \ 95 `
`:.\ text(When 95 is included, the median is 70 where as the mean is 72.25.)`
`72.25\ text(lies between his 6th and 7th scores and is, therefore, not a)`
`text(good measure of centre for Jason’s marks.)`
For the following set of data, state any outliers. (1 mark)
3, 5, 7, 7, 9, 10, 18
`18`
`text(The score of 18 is significantly different from the other scores)`
`:.\ 18\ text(is an outlier)`
The ages of boys competing in an inter-school futsal competition are shown in the frequency distribution table below.
\begin{array} {|c|c|}
\hline \textbf{Age (years)} & \textbf{Frequency} \\
\hline 13 & 4 \\
\hline 14 & 6 \\
\hline 15 & 11\\
\hline 16 & 6\\
\hline 17 & 3\\
\hline \end{array}
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\begin{array} {ll} \textbf{a.} & 30 \\ \textbf{b.} & 15 \text{ years} \\ \textbf{c.} & 15 \text{ years} \end{array}
| a. | `text( Number of boys)` | `= 4 + 6 + 11 + 6 + 3` |
| `= 30` |
| b. | `text( Mean age of boys)` | `= (13 xx 4 + 14 xx 6 + 15 xx 11 + 16 xx 6 + 17 xx 3)/30` |
| `= (52 + 84 + 165 + 96 + 51)/30` | ||
| `= 448/30` | ||
| `= 14.9333…..` | ||
| `~~ 15\ text(years (nearest whole number))` |
| c. | `text( Median age of boys )` | `= text(average of 15th and 16th scores)` |
| `= 15\ text(years, as both the 15th and 16th scores occur in 15 years)` |
A data set has a range of 50 and a mean of 20.
Give an example of a dataset using 4 numbers that satisfies this condition. (2 marks)
`0, 10, 20, 50`
`text(Note: other answers are possible.)`
`0, 10, 20, 50`
`text(Range) = 50 \ -\ 0 = 50`
`text(Sum of the numbers) = 20 xx 4 = 80`
`text(Mean) = (0 + 10 + 20 +50)/4\ = 80/4 \= 20`
`text(Note: other answers are possible.)`