7E Lesson 5/6 APK

Lesson 4 & Lesson 5:

Which of the following sums is the largest.

• 52-15

• 34+32

• 25-99

• -39+64

Answer explanation

52-15 = 37

32+34 = 66

25 - 99 = -74

-39 + 64 = 25

Therefore, 66 is the largest number.

Lesson 5:

- 46 - 17

• 29

• - 63

• 63

• 39

Answer explanation

Subtracting a positive integer moves to the right of the number line, in a more negative direction.

Lesson 5:

Tilly owed her sister $20, but has now payed back $8.

Select the correct number number sentence which represents this problem.

• -20 + 8 = -12

• 20 - 8 = 12

• -20 + 8 = 12

• 20 - 8 = -12

Answer explanation

Money owed is represented by negative numbers, and and money given back is represented by positive money.

-20 + 4 = -12

-12 represents that Tilly still owes her sister $12.

Lesson 6:

6 - (-3) =

• 3

• -3

• 9

• -9

Answer explanation

Subtracting a negative integer increases the value of an integer, which can be shown as moving to the right on the number line.

Lesson 6:

On Monday, Ruby made too much dinner so she decided to save her leftovers in the freezer which was set to -18 degrees Celsius. The following Thursday, she decided to put the leftovers in the fridge (set at 4 degrees Celsius) so it could thaw out whilst she was at work.

Determine the difference between the temperature of leftovers in the fridge and the freezer.

• 14

• -22

• 22

• -14

Answer explanation

Difference:

Larger Number - Smaller Number.

4 - (-18) = 22