Column Addition and Column Subtraction

Q: How do you line up digits for column addition?

Write the larger number above the smaller number and align the digits vertically by place value. Ones go under ones, tens under tens, hundreds under hundreds, and so on. Lining the columns up correctly is what makes every column total accurate when you start adding.

Q: What if the top digit is smaller than the bottom number in column subtraction?

You borrow 1 unit from the next column on the left. The borrowed unit turns the top digit into a two-digit number you can subtract from. The next column up drops by 1, so you keep track of it before moving on.

Q: Why do you add or subtract from the right column first?

You always start from the rightmost column. Any carried or borrowed digit then travels into the next column on the left. Working from right to left keeps the place value flow consistent for both column addition and column subtraction.

Key concept

Column addition and subtraction line up numbers by place value and work from the right. If a column makes 10 or more, you carry 1. If the top digit is too small, you borrow 1 from the left.

Column Addition and Column Subtraction - introduction visual

Video Lesson

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$Column Addition and Column Subtraction poster$

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Flashcards

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Column addition for 3425 + 782, showing how to align the numbers vertically. Start addition from the right, and carry over for sums over ten.

Column subtraction example showing how to subtract 876 from 2826, with steps including borrowing and aligning numbers, resulting in 1950.

How to Do Column Addition

Line up the digits vertically and start adding from the right
If a column totals 10 or more, carry 1 to the next column on the left

Practice Questions

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Q1Easy

$65 + 48 =$ ?

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Interactive Activity

Master column addition and subtraction

Top Number

458

Bottom Number

175

Calculation Steps

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Students Also Ask

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What does carrying over mean in column addition?

Carrying over happens when a column total has two digits. You write the ones digit below the line. Then you move the tens digit to the top of the next column. That carried digit gets added into the next column total, keeping every place value correct.

What is borrowing in column subtraction?

Borrowing is what you do when the top digit in a column is smaller than the bottom digit. You take 1 unit from the next column on the left. The top digit then becomes a two-digit number you can subtract from. The next column up drops by 1.

How do you line up digits for column addition?

Write the larger number above the smaller number and align the digits vertically by place value. Ones go under ones, tens under tens, hundreds under hundreds, and so on. Lining the columns up correctly is what makes every column total accurate when you start adding.

What if the top digit is smaller than the bottom number in column subtraction?

You borrow 1 unit from the next column on the left. The borrowed unit turns the top digit into a two-digit number you can subtract from. The next column up drops by 1, so you keep track of it before moving on.

Why do you add or subtract from the right column first?

You always start from the rightmost column. Any carried or borrowed digit then travels into the next column on the left. Working from right to left keeps the place value flow consistent for both column addition and column subtraction.

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