Video Transcript
Column Subtraction of Numbers up to
10,000: No Regrouping
In this video, we’re going to learn
how to use the standard algorithm or column subtraction to subtract numbers with up
to four digits when we don’t need to regroup. When we’re subtracting larger
numbers, like these four-digit numbers, it’s tricky to work the answer out in our
heads. So we need to use a written
method. We call this method column
subtraction. These are columns. We call the written method column
subtraction because columns are vertical. And when we use the column method,
we write each digit in its correct place value and subtract vertically. The most important thing to
remember is to make sure the digits line up correctly.
These are the ones digits, and we
always start by subtracting those first. Then we subtract the tens, the
hundreds, the thousands. And if we had a ten thousand digit,
we’d subtract in the ten thousands column next. A good way to make sure that you
write the digits in the correct place is to use squared paper. Now, we don’t get confused about
which digits to subtract. We always subtract the ones
first. The number 3,675 has five ones, and
2,342 has two ones. What is five take away two? It’s three. So we write our three in the ones
column. We really have to be careful to
make sure we write the digits in the correct place value.
Next, we subtract the tens. We have seven 10s, and we need to
take away four of them. What is seven take away four? It’s three. Seven 10s take away four 10s leaves
us with three 10s. Next, we subtract the hundreds. Six 100s take away three 100s
leaves us with three 100s. And finally, we need to subtract
the thousands. Three 1,000s take away two 1,000s
leaves us with one 1,000. 3,675 take away 2,342 is 1,333. Let’s practice what we’ve learned
by answering some questions now.
Use the place value counters to
solve 3,243 take away 1,232. Hint: 3,243 has been shown in the
place value table. What do you need to take away?
In this question, we have to
subtract 1,232 from 3,243, and we’ve been given a place value table to help. This shows the number 3,243. When we’re subtracting with large
numbers, like these two four-digit numbers, we need to use the standard written
method. We need to write each of the
numbers in their correct place value. We can see from the place value
table that 3,243 has three ones, and we need to subtract two because 1,232 has two
ones. The tens digit in the number 3,243
is four. So we’ve got four 10s, and we need
to subtract the three 10s in the number 1,232. There are two 100s in the number
3,243, and we need to subtract two. And 3,243 has three 1,000s, 1,232
has one, so we’re subtracting one 1,000 from our three 1,000s.
When we use the standard written
method or column subtraction, we always subtract the ones first. Let’s use our place value table and
the counters to help. We’ve got three ones, and we need
to subtract two. We know that three take away two is
one. Now we can subtract in the tens
place. We’ve got four 10s, and we need to
take away three 10s: one, two, three. We’ve got one 10 left. On to the hundreds place, we’ve got
two 100s, and we need to subtract two 100s. Here we go: one, two. We’ve got no 100s left.
Finally, we move into the thousands
place. We’ve got three 1,000s, and we need
to subtract one of them. And we know that three take away
one leaves us with two 1,000s. 3,243 subtract 1,232 equals
2,011. We used column subtraction and our
place value table and counters to help us subtract. First, we subtracted the ones, then
the tens, the hundreds, and the thousands. 3,243 take away 1,232 is 2,011.
Use column subtraction to calculate
the following: 6,458 subtract 3,226.
When we’re subtracting larger
numbers, it helps to use a written method. When we use the column subtraction
method, we subtract in columns, starting with the ones. Then we subtract in the tens
column, the hundreds column, and the thousands column. We could use a place value table to
help. The number we’re subtracting from
is 6,458. This is a four-digit number. The six digit is worth six 1,000s,
the four digit is worth four 100s, the five is worth five 10s, and the eight is
worth eight ones. And we’re subtracting 3,226.
Let’s start by subtracting in the
ones column. We’ve got eight ones, and we need
to subtract six. We know that eight take away six is
two, so we need to write our two in the ones column. Now we can move into the tens
place. What is five 10s take away two
10s? We know that five take away two is
three. So we need to write our three 10s
in the tens place. Moving into the hundreds column,
we’ve got four 100s and we need to take two away. And we know that four take away two
leaves us with two 100s. So we write that in our hundreds
place.
Finally, we can subtract the
thousands: six 1,000s take away three 1,000s. We know that six take away three
leaves us with three 1,000s. So let’s write that in the
thousands place. 6,458 subtract 3,226 is 3,232. We used column subtraction to
calculate the answer.
Use column subtraction to calculate
the following: 7,594 take away 482.
When we use column subtraction, we
subtract in columns. We start by subtracting the ones,
then the tens, the hundreds, and then the thousands. Let’s subtract. What is four ones subtract two
ones? Well, we know that four take away
two is two, so we can write the answer in the ones column. Now we can subtract the tens. We’ve got nine 10s, and we need to
take away eight 10s. Nine take away eight is one. So we’ve got one 10 left.
In the hundreds column, we’ve got
five 100s and we need to take away four. Five take away four is one. So we’ve got one 100 left. And in the thousands place, we’ve
got seven 1,000s and nothing to subtract, so we can just write the seven in the
thousands place. 7,594 take away 482 is 7,112. We used column subtraction to
calculate the answer.
What have we learned in this
video? We’ve learned how to use the
standard written method or column subtraction to subtract numbers up to 10,000. We also learned that we start
subtracting in the ones column and then move into the tens, the hundreds, and
thousands place.
