MULTIPLY BY POWERS OF 10
DIVIDE BY POWERS OF 10

PROBLEMS

Do the problem yourself first!

11.  True or false?

11.  a)  628 × 10 = 6,280  True.        b)  6.28 × 10 = 6.280  False.

11.  c)  6.28 × 10 = 62.8  True.

12.  Complete the following with either "left" or "right".

12.  a)  To multiply a decimal by 10, move the decimal point one place
12.  a)  right.

6.75 × 10 =  67.5

12.  b)  To divide a decimal by 10, move the decimal point one place
12.  b)  left.

6.75 ÷ 10 = .675

13.  Multiply each number by 10.  Then multiply by 100; by 1000.
13.  Move the decimal point.

 5.62 39.5 0.006 0.0035 × 10 56.2 395 0.06 0.035 × 100 562 3,950 0.6 0.35 × 1000 5,620 39,500 6 3.5

14.  Calculate by moving the decimal point or by adding on 0's.

 a)  3.46 × 10,000 = 34,600 b)  28 × 10,000 = 280,000 c)  0.009 × 100,000 = 900 d)  0.006 × 1,000,000 = 6,000 e)  2.5 × 10,000 = 25,000 f)  0.00002 × 100,000 = 2

15.  If one item cost \$2.45, then

15.  a)  10 will cost \$24.50.

15.  b)  100 will cost \$245.

15.  c)  1000 will cost \$2,450.

16.  a)  \$12.50 = 10 × \$1.25

16.  b)  \$125 = 100 × \$1.25

16.  c)  \$1,250 = 1000 × \$1.25

17.  Multiply each decimal by a power of 10 so that it becomes a whole
17. number.

16. a)  .8 × 10 = 8

16. b)  3.27 × 100 = 327

16. c)  .0051 × 10,000 = 51

18.  a)  If 2 pounds of cheese cost \$11.50, then how much will 20 pounds
16.  a)  cost?  10 times more:  \$115.

18. b)  If 4 pounds of coffee cost \$21.95, how much will 40 pounds
16. b)  cost?  \$219.50

19.  Divide each number by 10.  Then divide by 100;  by 1000.
17.  Move the decimal point..

 12.5 6.45 0.5 0.02 ÷ 10 1.25 0.645 0.05 0.002 ÷ 100 0.125 0.0645 0.005 0.0002 ÷ 1000 0.0125 0.00645 0.0005 2e-05

10.  Calculate by moving the decimal point.

 a)  68.4 × 10 = 684 b)  68.4 ÷ 10 = 6.84 c)  68.4 × 100 = 6,840 d)  68.4 ÷ 1000 = .0684 e)  .005 × 1,000,000 = 5,000 f)  .05 ÷ 10,000 = .000005

11.  Each number has how many decimal digits?

10.  a)  423.6  One.          b)  4.236  Three.          c)  4,236  None.

10.  d)  .05  Two.             e)  6.2000  Four.

12.  Calculate each column.  Separate the correct number of decimal
11.  digits.

 435 ÷ 10 = 43.5 92 ÷ 10 = 9.2 8 ÷ 10 = .8 435 ÷ 100 = 4.35 92 ÷ 100 = .92 8 ÷ 100 = .08 435 ÷ 1000 = .435 92 ÷ 1000 = .092 8 ÷ 1000 = .008 435 ÷ 10,000 = .0435 920 ÷ 10 = 92 8000 ÷ 100 = 80

13.  Divide by 10.  Then divide by 100.

 \$340 \$25 \$8.00 \$34 \$2.50 \$.80 \$3.40 \$.25 \$.08

14.  Complete the following with the correct operation -- multiplication 14.  or division by a power of 10.

 a)  1800 = 18 × 100 b)  3 = .003 × 1000 c)  .025 = 25 ÷ 1000 d)  .6 = 6 ÷ 10

Continue on to the next section.

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