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### Course: Arithmetic>Unit 17

Lesson 4: Multiplying and dividing with powers of 10

# Fractions as division by power of 10

Explore the concept of multiplying and dividing numbers by powers of 10. Understand how moving the decimal point to the left or right changes the value of a number, and how this relates to the concept of fractions as division. Created by Sal Khan.

## Want to join the conversation?

• Would it be the sames if was 10/34?
• No, if it was 10/34, it would not be the same. That is because the numerator and denominator are not the same now. The answer (I got it from a calculator) is :
0.29411764705882352941176470588235‬
• i actully really dont get it hot did he make 34/10 into 3.4
• Dividing by 10 is the same as moving the decimal point one place to the left.
Note that 34 has a hidden decimal point just to the right of the digit 4.
So 34/10 = 3.4

Have a blessed, wonderful day!
• So is this just dividing the two numbers to get the answer? At am. Please respond, people.
• No.You move the decimal over one spot for 10 ,two spots for 100 and so on.
• whats the difference of 0.1 and -1
• 0.1 and -1 have a difference of 1.1
0.1 is one tenth ABOVE zero while -1 is a whole one BELOW zero.
• so dividing to the power of ten is like dividing 1/the power of nine is like 1/ 90
• - Might I ask why is it dangerous? I know it looks puzzling, but is that the only reason?
• It's dangerous because people don't know what's be4 the 7.
• for some reason this one was A LOT harder than it should've been..
• hello from the other side
(1 vote)
• can a decimal have a decimal eg. 4.5.3? can that happen??
• I'm not whiz whatsoever but if I had to say, it would be no. A decimal denotes a fraction of a whole number. There is no such thing as a fraction of a fraction of a whole number.

The 1s place will always be there regardless of whether or not it's a 0 or another number.

4.5.3 is the same as saying 4 Ones, 5 Tenths, 3 Hundredths. The 2nd decimal doesn't contribute to the fraction in any way and shouldn't be placed there. In computer applications, version numbers are displayed with multiple decimals though.

in 4.5.3, 4 would mean the version number. 5 would mean small revisions done to version 4, and 3 would mean even smaller updates done to 4.5. So it would look something like Version 4 r5.3.
• why when you are multiplying you have to move it to the right but when you are dividing it goes to the left
• When you move the decimal point to the right by `1`, the number gets larger by being multiplied by `10`.
Eg. `2.56*10`: `2.56 -> 25.6` which made the number `10`x bigger.
When you move the decimal point to the left by `1`, the number gets smaller by being divided by `10`.
Eg. `25.6/10`: `25.6 -> 2.56` which made the number `10`x smaller.