Multiply by Powers of 10
0.2 x 101
= 0.2 x 10
= 0.2
2.5 x 2
5
.8 x .2 using a model
8 columns, 2 rows filled in
16 hundredths is in the crossover
0.16 or .16
What is the volume of a box that is 2 inches long, 4 inches wide, and 3 inches tall?
24 cubic inches
1.235 x 102
1.235 x 100
= 123.5
3.44 x 2
6.88
.2 x 1.3
.26 or 0.26
What is the area of a 4 by 5 rectangle?
20 square inches
10.23 x 103
10.23 x 1000
move the decimal right 3 times
10230
5.689 x 7
39.823
.78 x .56
0.4368
(multiply then move the decimal back 4 times)
A chocolate bar costs 3.25. How much will 4 candy bars cost?
3.25 x 4 = $13.00
2.345x 105
234500
5.63 x 9
50.67
17.5 x 8.4
147
A rectangle is 0.8 inches long and 0.2 inches tall. What is the area?
0.16 inches
0.0063 x 106
0.0063 x 1,000,000
move decimal point 6 to the right
6300
*remember, no extra zeros at the beginning of a number
9.2 x 8
73.6
12.5 x 1.63
20.375
A rectangle is 3.9 inches long and 12.5 inches wide. What is the perimeter?
32.8 inches