Lesson Video: Column Subtraction of Numbers up to 10,000: Regrouping | Nagwa Lesson Video: Column Subtraction of Numbers up to 10,000: Regrouping | Nagwa

# Lesson Video: Column Subtraction of Numbers up to 10,000: Regrouping Mathematics

In this video, we will learn how use the standard algorithm to subtract numbers with up to four digits when we have to regroup.

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### Video Transcript

Column Subtraction of Numbers up to 10,000 with Regrouping

In this video, we’re going to learn how to use the standard written method to subtract numbers with up to four digits when we have to regroup. In this example, we’re subtracting a four-digit number from a four-digit number. And we’ve modeled the number we’re subtracting from using place value counters.

3,550 has three 1,000s, five 100s, five 10s, and no ones. And we have to subtract 1,782. When we add or subtract using the standard written method, we always start in the ones column first. We have a problem. 3,550 has zero in the ones place. So there’s nothing for us to subtract from. And we need to take away two ones. Because zero is less than two, we’re going to need to regroup. We’re going to need to take a 10 from the tens column. So we need to take one 10 and exchange it for 10 ones.

So now we’ve got four 10s in the tens column. And we’ve got enough ones to subtract from in the ones column. What is 10 take away two? 10 ones take away two ones leaves us with eight ones. Now we can move into the tens column to subtract. We’ve got four 10s left, and we need to subtract eight. Four is less than eight, so we’re going to need to regroup again. We’re going to need to take 100 and exchange it for 10 10s. So we’ve got four 100s left, and we have 14 10s ready to subtract from. What is 14 take away eight? It’s six. We’ve got six 10s left.

Now we can move into the hundreds column to subtract. We’ve got four 100s, and we need to subtract seven. We need to regroup again. We need to take 1,000, which leaves us with two 1,000s, and exchange it for 10 100s. Now we’ve got 14 100s, and we need to subtract seven. 14 100s take away seven 100s leaves us with seven 100s.

Finally, we can subtract in the thousands place. We’ve got two 1,000s left, and we need to subtract one. Two 1,000s take away one 1,000 leaves us with one 1,000. So 3,550 subtract 1,782 equals 1,768. We had to do a lot of regrouping.

If the number on the top row of the calculation is less than the number on the bottom, we have to regroup. In the ones column, we had zero, which is less than two. We can’t subtract two from zero, so we had to regroup. The four digit in the tens column is less than the eight digit in the tens column. So we had to regroup again. And we had the same problem when we came to subtract in the hundreds place. Four is less than seven. So we regrouped again.

Now that we’ve thought about how to regroup when we’re subtracting four-digit numbers from four-digit numbers, let’s try answering some questions.

Find the result of the following subtraction: 6,882 subtract 4,357.

In this question, we have to use the standard written method to subtract 4,357 from 6,882. Both of our numbers have four digits, which means they have a thousands digit, a hundreds digit, a tens digit, and a ones digit. And we always start by subtracting in the ones column first.

We could use a place value table and counters to help us model the number we’re subtracting from. 6,882 has six 1,000s, eight 100s, eight 10s, and two ones. And we’re going to subtract the ones first. We’ve got two ones, and we need to subtract seven. This is a problem because two is less than seven. We don’t have enough ones to subtract seven from. We’re going to need to regroup. We need to take one of our tens and exchange it for 10 ones. Now that we’ve got 12 ones, we can subtract seven, which leaves us with five ones.

Now we can subtract in the tens place. We’ve got seven 10s, and we need to subtract five. Seven 10s take away five 10s leaves us with two 10s. Now we move into the hundreds place. What is eight 100s take away three 100s? We’ve got five 100s left. Eight take away three is five. Now what we need to do is subtract the thousands. We’ve got six 1,000s, and we need to take away four, which leaves us with two 1,000s. 6,882 subtract 4,357 is 2,525.

Find the result of the following subtraction: 9,213 subtract 425.

In this question, we have to subtract using the standard written method. We always start by subtracting in the ones column. We’ve got three ones, and we need to subtract five ones. But three is less than five, which means we’re going to need to regroup. We need to take a 10 and exchange it for 10 ones. Now we’ve got 13 ones. We can subtract five. 13 take away five leaves us with eight ones.

Next, we need to subtract in the tens column. There are no tens, and we need to subtract two 10s. And since zero is less than two, we’re going to have to regroup again. We need to take one of our hundreds and exchange it for 10 10s. So now we have 10 10s, and we need to take away two. And we know that 10 10s take away two 10s leaves us with eight 10s.

In the hundreds place, we’ve got one 100, and we need to subtract four 100s. Again, since one is less than four, we have to regroup. We need to take 1,000 and exchange it for 10 100s. Now we’ve got 11 100s. We can subtract four, which leaves us with seven 100s. Finally, we can subtract the thousands. There are eight 1,000s and nothing to subtract, which means we’ve got eight 1,000s left. 9,213 subtract 425 equals 8,788.

Perform the following column subtraction: 9,201 subtract 2,468.

In this question, we have to subtract a four-digit number from a four-digit number using the standard written method. We always start by subtracting in the ones column. 9,201 has one one, and 2,468 has eight ones. But one is less than eight. We don’t have enough ones to subtract eight from. So we need to regroup. So we need to look to the tens column. But there’s zero in the tens place. So we need to take a hundred from the hundreds column and add it to the tens column. So now we have 10 10s. We need to take one of these tens, so we’ve got nine left now, and exchange it for 10 ones.

Now that we’ve got 11 ones, we can subtract our eight ones. 11 take away eight is three. Now we can move into the tens place. We’ve got nine 10s, and we need to subtract six 10s. Nine take away six leaves us with three 10s. Moving into the hundreds column, we’ve got one 100, and we need to take away four 100s. We know that one is less than four, so we don’t have enough hundreds to subtract from. We’re going to need to exchange again. We need to take one of our thousands and exchange it for 10 100s. Now we’ve got 11 100s. We can subtract four. 11 100s take away four 100s leaves us with seven 100s. Finally, we can subtract in the thousands column. We’ve got eight 1,000s, and we need to subtract two 1,000s. And we know that eight take away two leaves us with six 1,000s. 9,201 subtract 2,468 equals 6,733.

What have we learned in this video? We’ve learned how to use the standard written method to subtract numbers with up to four digits when we have to regroup.