Question Video: Subtracting Two Multidigit Numbers Mathematics

Video Transcript

81,252 take away 21,439 equals what.

In this question, we have to choose an appropriate way to calculate 81,252 subtract 21,439. These are both five-digit numbers. It’s quite a tricky calculation to do mentally, so we could subtract using the standard written method or column subtraction. We’re starting with the number 81,252 which we’ve modeled using place value counters, and we need to subtract 21,439. So, let’s start by subtracting the ones.

We’ve got two ones, and we need to subtract nine. So, we’re going to need to regroup. We need to take one of our 10s and exchange it for 10 ones. Now, we’ve got 12 ones, and we can subtract nine. We know that 12 take away nine is three. Now, we can subtract in the tens column. We’ve got four 10s, and we need to take away three. Four 10s take away three 10s leaves us with one 10. We’re going to need to regroup again. We’ve only got two 100s, and we need to subtract four. So, we can take one of our thousands, which is our only 1000 and exchange it for 10 100s. Now, we’ve got 12 100s, and we can subtract four. 12 take away four leaves us with eight 100s.

We’re going to need to regroup again. We’ve got no 1000s, and we need to take away one. So, we can take one of our 10 1000s and exchange it for 10 1000s. Now, we’ve got 10 1000s. We can subtract our one. And we know that 10 take away one is nine. Now, what we need to do is subtract in the 10 thousands column. We’ve got seven 10 thousands left, and we need to subtract two. We know that seven take away two is five. So, 81,252 subtract 21,439 equals 59,813.

Because we were subtracting a five-digit number from a five-digit number, we decided to use the standard written method or column subtraction. And we had to do quite a lot of regrouping. So, we used the place value table and counters to help us keep track. 81,252 take away 21,439 equals 59,813.