2. • 1, 10, 100, 1000, 10000, etc. are all
powers of 10
• These numbers can be written
using exponents
• 1 = 10
• 10 = 10
• 100 = 10
• 1000 = 10
• 10000 = 10
What are powers of
10???
4
1
2
3
0
3. What are exponents?
• An exponent tells us how many
times to multiply a number by
itself
• For example
– 10
– This tells us to multiply 10 x 10
– 5
• This tells us to multiply 5 x 5 x 5
2
3
4. Powers of 10
continued…
• The fractions
etc… are also considered
powers of ten.
– In decimal form they can be
written 0.1, 0.01, 0.001, 0.0001,
etc.
1
10
1
100
1
1000
1
10000
5. Multiply by Powers of
10
• To multiply a number by a power of 10
like 10, 100, or 1000, we just have to
move the decimal point to the right an
appropriate number of places.
• To multiply by 10 we move one place
• To multiply by 100 we move two places
• To multiply by 1000 we move three
places and so on.
6. Multiply by Powers of
10
• Here are some examples:
1.25 x 10 = 12.5
1.25 x 100 = 125
1.25 x 1,000 = 1,250
1.25 x 1,000,000 = 1,250,000
7. Multiply by Powers of
10 using exponents
• With the same examples as the
previous slide, we can use exponents to
multiply by powers of 10
1.25 x 10 (move decimal to right once)
1.25 x 10 (move decimal to right two times)
1.25 x 10 (move decimal to right three times)
1.25 x 10 (move decimal to right six times)
**The exponent tells us how many times
to move the decimal point to the right
1
2
3
6
8. Multiply by Powers of
10
Do some by yourself.
• 3.8 x 10 = __________
• 3.8 x 10 = __________
• 3.8 x 10 = __________
• 3.8 x 10,000 = __________
3
7
9. More difficult examples
• 1,280 x 1,000 = 1,280,000
• 0.026 x 10 = 2.6
• 10.0036 x 1,000 = 10,003.6
• 4.99 x 10 = 49,900
2
4
10. Dividing by powers of
10
• Dividing is just as easy; the
decimal place simply moves to the
left instead of to the right.
250.6 ÷ 10 = 25.06
250.6 ÷ 100 = 2.506
250.6 ÷ 10 = 0.02506
250.6 ÷ 10 = 0.0002506
4
6
11. Dividing by
Powers of 10
• Do some by yourself.
375 ÷ 10 = __________
375 ÷ 10 = __________
375 ÷ 100 = __________
375 ÷ 10 = __________
0
4
9
