Adding, Subtracting, Multiplying, and Dividing Decimals! And a few fractions

Multiplication

100

When you multiply decimals you should first ignore the ________ ______?

Decimal Points

200

After multiplying the two decimals how do you decide how many decimal places the answer will have?

Count up the number of decimal places in the problem.

300

.2 x 3

.6

400

.02 x 11

.22

500

.21 x 11

2.31

Division

100

When you divide decimals you should first move the decimal point in the divisor (the number outside the division bar) to the ______________________?

Far right (just past the ones place)

200

8 / 25 

0.32

300

Divide 2.4 by .2 

12

400

Divide 24.3 by .03

810

500

Divide 6.48 by .4

16.2

Addition

100

When you add decimals you should first line up the __________ ___________. Then add some ______ if you need them.

Decimal Points zeros

200

2.23 + 4.1

6.33

300

1.33 + .2

What is 1.53

400

2.11 + 5.2

7.31

500

3.66 + 44.1

47.76

Subtraction

100

When you subtract decimals you should first line up the ________ _______? Then add some _______ if you need them.

decimal points zeros

200

2.44 - 1.1

1.34

300

34.67 - 2.1

32.57

400

5.33 - .2

5.13

500

22.567 - 1.22

21.347

Random

100

412 - 179.789

232.211

200

0.3935 + 0.64

1.0335

300

8.10 / 1.1 (Hint: Stop when you get to the thousandths place)

7.363

400

7.89 x 12.3

97.047

500

78.1 + (6/4) x (4.5 x 7.2) - 0.501

This is worth 2000 points. 

126.199