7th Grade Operations with Numbers Review

Adding Numbers

100

11 + (-7)

= 4

200

-17 + (-12)

= -29

300

-2.91 + 4.7

= 1.79

400

-1/6 + 3/4

= -2/12 + 9/12

= 7/12 

500

A submarine was stationed 800 feet below sea level. If it ascends 530 feet, what is its new position?

-800 + 530

=-330 ft below sea level

Subtracting Numbers

100

-7 - 7

= -7 + (-7)

= -14

200

54 - (-17)

= 54 + 17

= 71

300

3.42 - 7.71

= 3.42 + (-7.71)

= -4.29

400

-1/5 - (-1/10)

= -1/5 + 1/10

= -2/10 + 1/10

= -1/10

500

In Buffalo, New York, the temperature was -14^oF in the morning. If the temperature dropped 7^oF at night, what is the temperature at night? Write and solve an expression. 

-14 - 7

= -14 + (-7)

= -21^oF

Multiplying Numbers

100

-5(8)

= -40

200

-13 • -4

= 52

300

-2.5 • (-6.7)

= 16.75

400

-2/3 • 5/6

Simplify. 

-2/3 • 5/6

= -10/18

= -5/9

500

A local store reported losing $24 each day for 4 days. How much did they lose in total? Write and solve and expression.

-24 • 4

= -$96

Dividing Numbers

100

-28 ÷  4

= -7

200

-108 ÷ (-4)

= 27

300

-3.528 ÷ 0.03

= -117.6

400

-4/3 ÷ (-6/10)

-4/3 ÷ (-6/10)

= -40/30 ÷ (-18/30)

= -40/30 •  (-30/18)

= 40/18 = 2  4/18 

= 2  2/9

500

A local store reported losing $55 for a total of 5 days. How much did they lose each day?  Write and solve an expression. 

-55 ÷ 5

= -$11

Order of Operations

100

-34 - 21 + 16

= -34 + (-21) + 16

= -55 + 16

= -39

200

42 ÷ (-7) • 2

= (-6) • 2

= -12

300

4 + (-3 • 2) • 5

= 4 + (-6) • 5

= 4 + (-30)

= -26

400

|-5 • 2| + (-24) ÷ 2

= |-10| + (-24) ÷ 2 

= 10 + (-24) ÷ 2 

= 10 + (-12)

= -2

500

4 ⋅ (−6) + 12 ÷ |2 − 8|

= 4 ⋅ (−6) + 12 ÷ |−6|

= 4 ⋅ (−6) + 12 ÷ 6

= −24 + 12 ÷ 6

= −24 + 2 

= −22