ffirs.indd

72 Speed Math for Kids
Write 5 as the next digit of your answer. Your calculation should
now look like this:
0123 × 11
53
Continue the same way:
1 + 2 = 3
0 + 1 = 1
Here is the fi nished calculation:
0123 × 11
1353
If we hadn’t written the 0 in front of the number to be multiplied,
we might have forgotten the fi nal step.
Th is is an easy method for multiplying by 11. Th e strategy develops
your addition skills while you are using the method as a shortcut.
Let’s try another problem. Th is time we will have to carry digits. Th e
only digit you can carry using this method is 1.
Let’s try this example:
471 × 11
We write the problem like this:
0471 × 11
We add the units digit to the digit on its right. Th ere is no digit to
the right, so 1 plus nothing is 1. Write down 1 below the 1. Now
add the 7 to the 1 on its right:
7 + 1 = 8
Write the 8 as the next digit of the answer. Your work so far should
look like this:
0471 × 11
81