# math skills 3: Powers of 10

(10^2*10^3)^(-2)=

0.0000000001

10^-4 10^-2 10^-1 10^-3

0.0001 0.01 0.1 0.001

10^0 10^1 10^2 10^8

1 10 100 100000000

10^3×10^−2=

10

(10^3*10^2)+ 10^(-3)=

100,000.001

10^4÷10^−1=

100000

A typical galaxy contains about 100 billion stars, and there are approximately 100 billion galaxies in the observable universe. About how many stars are in the observable universe?

10^22

Identify the equations below that are true. You may wish to watch the video Powers of 10, Part 3 for a review of operations (adding, subtracting, multiplying, dividing) with powers of 10.

10^5/10^3=10^(5−3) 10^5÷10^3=10^(5−3) 10^5×10^3=10^(5+3) (10^5)^3=10^(5×3)

Powers of 10 make it very easy to write large and small numbers, but as a result it can also be easy to forget the large differences between different powers. We can compare any two numbers by dividing them. For example, we say that 12 is four times as large as 3 because 12÷3=4. Complete the sentences below comparing pairs of powers of 10.

10^80 10 times as large as 10^79 10^-1 is 1000 times "" 10^-4 10^-2 is 1/10 '''10^-1 10^-4 is 1/1000 "" 10^-1 10^5 is 100 '''' 10^3 10^2 10000'''' 10^-2 10^10 is 1000000000 '''' 10^1