The word “borrow” is something many of us learned in elementary school.
When we had to subtract and didn’t have enough ones, our teacher taught us to “borrow” from the tens.
But are we really borrowing?
Not quite. We actually have enough — we just need to rename what we have.
This time, let’s look at 34 − 16 and see what is really happening.
34 = 3 tens and 4 ones.
16 = 1 ten and 6 ones.
Same as addition, let’s look at the ones place first.
We have 4 ones, but we need to take away 6 ones.
It looks like we don’t have enough ones.
But remember: 10 ones = 1 ten.
So instead of saying we’re “borrowing,” let’s rename 1 ten as 10 ones.
Let’s illustrate this using candies.
We have 4 candies, but we want to give 1 candy to each of our 6 friends. Do we have enough?
No. We only have 4 candies, but we need 6.
Let’s open one of the packs of 10 candies and turn it into 10 individual candies. This is the renaming method.
Now we have another 10 candies, that make 14 candies in total. Now can we give each to our 6 friends? Yes.
14 ones – 6 ones = 8 ones.
Next step, subtract the tens.
As a while ago we opened another pack of candies, we only have 2 packs of candies left.
2 tens – 1 ten = 1 ten.
Therefore, 34 – 16 = 18.
When we don’t have enough ones, we don’t really “borrow.”
The amount stays the same — we’re simply looking at it in a different way.
Once we understand the renaming, the “borrowing” method starts to make much more sense.
Happy teaching! I hope math feels a little simpler at home.
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