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.