First of all, we will use the first two panels on the cloth to lay out the two numbers we are adding together. I am going to do the sum 44 - 23. Notice I am calling this a "take away." This is because we are literally going to take counters away.
Put the number we are taking from on the left and the number we are taking away on the right.
Work from the top down. See how there are two counters to take away in the right column on the x or 10s line? There are (at least) two to match it in the left.
Using both hands, take the same number of counters from the same line on both sides at once. I like to match finger to finger, starting one at a time, touch one from each column and pull it away. The picture here shows 2 at a time, but be careful and don't hurry, that's the way mistakes are made.
We now have 24 - 3. Note that 44 - 23 = 24 -3, we haven't cheated anywhere.
Do the same on the next line down
And there's uncle Bob again.
Lay out the sum as before, here we have 83 - 54.
Work from the top down.
OK, the 50s match, that's fine.
I have no 10s to take away, so we can skip that line.
Uhoh, I have four 1s to take away and only three 1s to take from, what do I do?
Well, let's take the 1s we can...
OK, done that, what next? I need some ones to take away from.
Now we need to do the opposite of tidying up. Working downwards, start taking one counter from the highest row and replacing it with the same value the next row down. So take one 10 (x) and replace it with two 5s (vv)
And take one 5 (v) and replace it with five 1s (iiiij).
We now have some 1s on the bottom row, and so we can take away the 1 we need to
To get the answer.
You need to be pretty confident with addition and subtraction and tidying up and its opposite, and generally keeping track of where you are before going on to multiplication or division.
Go to:
Multiplication
Division
Introduction
Addition
