Operations with Rational Numbers

Add

100

2.3 + 12.8

15.1

200

1/3  +  3/7

16/21

300

8/9 + (-5.6)

-4.71111111111111111111111111111111111111111

400

-2 4/5 + 1.2

4

500

6 5/8 + 3 2/3

10 7/24

Subtract

100

6.5 - 2.6

3.9

200

8/9 - 3/4

5/36

300

-7.5 - 1/4

-7.75

400

4 1/5 - (-3.6)

7.8

500

-3 2/5 - (-1 1/2)

-1 9/10

Multiply

100

5.3 x 3.2

16.96

200

1/5 x 1/2

1/10

300

3/4 x (-3.5)

2.625

400

2.7 x -4 4/5

-12.96

500

(5 1/2)(3 5/6)

21 1/12

Divide

100

9.8 / 6

1.63333333333333333333333333333

200

4/5   /      1/2

1 3/5

300

-8.4 /      3/4

-11.2

400

7.5   /       2 1/2

3

500

-9 1/2      /      (-3 1/4)

2 12/13

Riddles

100

A lily pad on a small pond doubles in size every day. On day 20, it covers the whole pond. On what day was the lily pad the size of half the pond?

Day 19

200

There are seven apples and you take away three of them. How many apples do you have?

3

300

Multiply this number with any other number and you will always get the same answer. What’s the number?

0

400

What can you hold in your left hand but not in your right?

Your right elbow

500

You see a boat filled with people. It has not sunk, but when you look again you don’t see one Single person on the boat. Why?

They are all married