Video Transcript
Find the result of the following:
865 subtract 384 equals what.
We don’t really need to think about
which method we want to use to find the answer to the subtraction. It’s been set out as a column
subtraction already for us. So we’ll use the standard written
method. First, we subtract the ones. 865 has five ones, and 384 has four
ones. And the difference between five
ones and four ones is one one. Onto the tens. 865 contains six 10s, and 384
contains eight 10s. At the moment, we can’t subtract
eight 10s. We don’t have enough 10s in our
tens column. We’re going to need to regroup our
starting number. We’ll start by taking one of our
100s. Instead of eight 100s, we now have
seven 100s. And we need to regroup this into 10
10s. So instead of six 10s in our tens
column, we can put a little one to show we have 16 10s.
We haven’t changed the value of our
starting number at all. Seven 100s, 16 10s, and five ones
are exactly the same as 865. But by regrouping the number like
this, we do have enough 10s to subtract eight 10s. So we have 16 10s; we need to take
away eight 10s. We know that eight and eight makes
16, so we’re going to be left with eight 10s. Finally, the hundreds, 865 has
eight 100s, and 384 has three 100s. But don’t forget, we’re not
subtracting three from eight 100s because we’ve exchanged one of our 100s. We’ve only got seven 100s left in
the hundreds place. So seven 100s subtract three 100s
leaves us with four 100s. 865 subtract 384 equals 481.
