Adding & Subtracting Rational Numbers

Adding Fractions

100

-5  1/3  +  8  2/3

3  1/3

200

4  5/6  +  (-1  2/3)

3  1/6

300

-18  7/9  +  7  4/9

-11  1/3

400

3  1/4  +  7  3/4

11

500

-12  7/8  +  (-2  1/2)

-15  3/8

Subtracting Fractions

100

-8  1/2  -  4

-12  1/2

200

7  3/8  -  (-2  1/8)

9  1/2

300

-26  2/5  -  (-11  1/5)

-15  1/5

400

14  1/7  -  (-3  3/14)

17   5/14

500

-5  3/6  -  (-10  2/3)

5  1/6

Adding Decimals

100

-13.4 + 8.6

-4.8

200

7.51 + 22.08

29.59

300

-41.90 + 22

-19.90

400

117.4 + 8.93

126.33

500

-328.17 + 63.40

-264.77

Subtracting Decimals

100

-3.7 - 14.9

-18.6

200

22.43 - 4.07

18.36

300

-81.36 - 41.93

-123.29

400

7.85 - ( -31.03)

38.88

500

206.14 - 131.78

74.36

Math Rules

100

Double Jeopardy! 

How do you determine what sign the sum of a negative and a positive number makes?

The answer will have the same sign as the number with the greatest absolute value (aka the bigger number if you ignore the signs). 

200

Part 1 - What is the sign of the sum of two negative numbers? 

Part 2 - What is the sign of the sum of two positive numbers?

Part 1 - Negative 

Part 2 - Positive

300

Give one of the phrases we learned to remind us how to change a subtraction sentence into an addition sentence.

Add the Opposite 

Keep, Change, Change

Additive Inverse

400

What has to be done before you can add or subtract fractions?

Least Common Denominator

500

What has to be done before you can add or subtract decimals?

Line up the decimal points (and the place values)