Look For The 10's - Addition Made Easy

Here we will look at a more user friendly approach to addition. When you are finished reading, why not try out the Look for the 10's quiz?

Our number system is based on 10's. This is especially true with addition. Don't believe me? Ask yourself this:

Which is easier to add?

57 + 26

or

40 + 20

Adding numbers that have zeros as their last digits is much easier than adding numbers with many different digits. This is because the zeros can essentially be ignored when you're doing the sum. 

Another issue that affects a lot of people is the manner in which they were taught to add. Normally children are shown to add by summing the units, and then carrying any tens to the left. While this obviously works, it has some serious drawbacks. Firstly it confuses many people, who end up following a method rather than engaging with the problem. Secondly it does not work very well as a method of mental arithmetic.

Like most people I learned to do addition in the manner mentioned above. However over time I realised that there is a faster and easier way to do problems like this, which can be 'summed up' (excuse the pun) as Look for the 10's.


Put simply, you find groups of tens, and add them. That's essentially it. This approach works best when you are adding numbers and you need to 'carry' digits, but it can be used for any sum.


Let's start with the sum mentioned above. To make this explanation simpler, let's pretend we're adding apples. That just makes things a little bit easier to visualize. So we have two piles of apples. One pile has 57 apples in it, the other has 26. So we have to calculate

57 + 26

Try looking at the biggest number.

57

If we could turn that into a number that ended in zero, it would be easier to do the addition. How about trying to make it into 60?

Well if we want to turn 57 into 60, we will need to add 3 to it. So instead of taking the whole pile of 26 apples, we can just take three of them. We put them with the 57 apples to get 60. Now we have a pile of 60 apples, and another pile of 23 apples.

 60 + 23

Let's ignore the 3 for a moment and just Look for the 10's.

60 + 20

That's fairly simple to add, as 60 + 20 = 80. Now just put the 3 we ignored back in there to get 83. Now we know

57 + 26 = 83

So we have our answer.

In step by step form the Look for the 10's approach to addition would be:

1. Change one number so that it ends in 0.
2. Add the tens.
3. Just put the units back on the end.

Let's try one more example. How about:

68 + 34 

Look at the 68. How many apples do we need to take from the other pile to make 70? Only 2. So now our sum is:

70 + 32

Well you can see that 

70 + 30 = 100

And then we put the 2 back in there to get 102. So:

68 + 34 = 102

I don't know about you, but for me this is a faster and easier way to do addition. Why not try it out with some of the questions in the Look for the 10's quiz? There's no time limit, so take your time and see how this approach works for you. You can also try out one of the math games at the bottom of the page. Thanks for reading and feel free to tell us what you think in the comments!