Adding 2-Figure Numbers

  • Adding 2-figure numbers that involve a carry figure
  • Adding from right to left
  • Adding left to right

Adding from Right to Left

The traditional way to add, say, 56 + 26 is to put the numbers under each other and add from right to left.

    56
+ 26
    82
    1

First, in the units: 6+6=12, so put down 2 and carry 1.

Then adding the tens: 5+2=7, and adding the carried 1 you get 8.

So the answer is 82.

Adding from Left to Right

When an addition sum has a carry, like 56 + 26, you can add it in your head like this:

In 56 + 26 you get 7 tens or 70

Then in the units you have 6 + 6 = 12

And 70 + 12 = 82.

Left to Right Written Down

What if you want to write down the left to right method: for example, to show your ‘working out’ in an exam?

You write it like this:

56 + 26 = 712 = 82

Notice you write the 12 as 12 to show that the 1 in the 12 has to be carried to the left.

Similarly, 48 + 45 = 813 = 93.

The Preferred Method

Working from left to right has many advantages: it’s more natural, there’s less to remember, and there’s less chance of making mistakes. Therefore, in this course we will favor the left to right method.

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