Multiplying Decimals by 10, 100 and 1000. Multiplying by 10. When a decimal
number is multiplied by 10, you move all of the digits one place to the left e.g.. 7.
5.
Multiplying Decimals by 10, 100 and 1000 Multiplying by 10 When a decimal number is multiplied by 10, you move all of the digits one place to the left e.g.
7
5
5
2
2
Becomes…
7
So each digit moves one place to the left. Multiplying by 100
The decimal point does not move and does not need to be counted when digits move.
This works the same, but we move all of the digits 2 places to the left e.g.
4
3
Becomes…
4
3
0 If there is a space in a whole number column, we fill it with a zero.
Multiplying by 1000 Each number moves 3 places to left. Remember this by looking at the number of zeros – 1000 has three zeros so move the digits three places, 100 has two zeros so it moves 2 places and 10 has one zero so we only move the digits one place.
6 X 1000 =
6
3
1
0
3
1
Dividing by 10 Dividing by 10 works the same as multiplying but the numbers move to the right (they get smaller).
1
2
0
1
Becomes…
2
We fill in any spaces with zeros. Dividing by 100 We move all of the digits 2 spaces to the right e.g.
5
2
3
0
5
Divided by 100 =
0
2
3
When dividing by 10, 100 and 1000, we need to fill any gaps in our decimal columns with zeros. Dividing by 1000 Just move the digits 3 places to the right.
