Transcript Multiplying and dividing by 10 and 100 is easy…..

Multiplying and dividing
by 10 and 100 is easy…..
…when you know how!
Make sure you keep an eye on the
place – value markers…they’re
REALLY important.
Th
H
T
3
U
2
.
.
t
1
h
0
Multiply it by 10, so every digit becomes 10 times
BIGGER. EVERY digit moves one place to the LEFT.
Th
H
3
T
3
2
U
2
1
.
.
.
t
1
0
h
0
Lets look at that again…
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We’ll multiply 56.03 by 10.
Remember what happens to EACH
digit.
Th H T U . t h
5 6 . 0 3
X10
5 6 0 . 3
Check that the order of the digits is
the same as when you started.
So what happens when you
multiply by 100…let’s see
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TH H T U . t h
4 6 . 0 2
4
6 0 2 .
X 100
See! Each digit moves across two places
to the left…and of course
100 has 2 zeros, so that’s a good reminder.
The number becomes 100 times bigger
Now if you make numbers bigger by
moving them to the left…what do you
think happens when you divide numbers
by 10?
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Yes… you move each digit one place to the
right, to make it 10 times smaller!
Like this…

TH H T U . t
3 5 0 . 0

3 5 . 0


h
0
REALLY IMPORTANT!!!!!!!!!! See how the decimal point stays
inn the same place.
So now you can guess what
happens when you divide by
100.
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That’s right, every digit moves two places to
the right to make the number 100 times
smaller.
Lets divide 12.6 into 100 bits…wow how tiny
would each bit be?
TH H T U . t h th t.th
1 2 . 6 0
divided by 100
0 . 1 2 6 0
So 0.1260 is 100 times smaller than 12.6