Rational Number Operations

Adding

100

-3/4 + (-8/9)

-1 23/36

200

5 1/3 + 7.5 + (-3 1/6)

9 2/3

300

-4.2 + 8.1 • (-1.9)

-19.59

Subtracting

100

-4.62 – 3.51

-8.13

200

-1 3/4 + 8 1/3 + 4 1/4

10 5/6

300

(-2/3)^2–3/4(2 1/3)

-1 11/36

Multiplying

100

-0.05 • (-0.5)

0.025

200

5/6 • (-4 1/2) • (-2 1/5)

8 1/4

300

If a and b are negative integers, and x and y are negative integers, what is the sign of this expression. Explain.

(a+b)/(x+y)

Positive. Because a negative divided by a negative is positive.

Dividing

100

3/8 ÷(-9/5)

-5/24

200

(7/6)/((-11/5)(10 1/2)(-5/11)

1/9

300

Which of the following are equivalent to 

1/-7*(-2/3)^2*|1-3|

Choose all that apply.

A) 4/9*2*-1/7

B) -1/7*|-8+6|*(1/3+1/9)

C)  None of the above

A and B

MATHCOUNTS

300

In a group of students, 12 are taking chemistry, 10 are taking physics, 3 are taking both chemistry and physics, and 5 are taking neither chemistry nor physics. How many students are in the group?

24