Super Columns for Subtraction! Taking Away 2-Digit Numbers (The Easy Way!)

Hello Maths Explorers! We’ve learned how to add using columns, and now it’s time to learn how to subtract using columns! This is called Column Subtraction. It’s a super neat way to organize your numbers when you’re taking one away from another. We’ll start by subtracting a 2-digit number from another 2-digit number, and for these first problems, there’s no regrouping (that means no “exchanging” or “borrowing” needed). It’s nice and straightforward!

What is Column Subtraction? Let’s Learn the Steps!

Column subtraction helps us take away numbers by lining them up carefully based on their place value – ones with ones, and tens with tens. This makes sure we subtract the correct parts of the numbers.

Let’s Subtract Two 2-Digit Numbers: Example 48 − 25

Here’s how you set it up and solve it:

Step 1: Write the numbers one above the other. Put the bigger number on top. Make sure the ones digits are lined up in one column, and the tens digits are lined up in another column.

   T O  (T for Tens, O for Ones)
   4 8
−  2 5  (The minus sign goes on the left)
------  (Draw a line underneath for your answer)

Step 2: Subtract the Ones Column First. Always start with the ‘Ones’ (O) column on the right. In our example, it’s 8 take away 5 (8 − 5). 8 − 5 = 3. Write the answer (3) directly below the ones column, under the line.

   T O
   4 8
−  2 5
------
     3

Step 3: Subtract the Tens Column Next. Now look at the numbers in the ‘Tens’ (T) column. In our example, it’s 4 take away 2 (4 − 2). 4 − 2 = 2. Write the answer (2) directly below the tens column, under the line.

   T O
   4 8
−  2 5
------
  2 3

So, 48 − 25 = 23! You’ve used column subtraction!

For all the questions on this page, the top digit in each column will be bigger than or the same as the bottom digit, so you won’t need to worry about borrowing.

Practice Your Column Subtraction Skills! (18 Questions)

Ready to try setting up and solving some column subtractions? Here are 18 questions where you’ll subtract one 2-digit number from another. Remember to line up your ones and tens carefully, put the bigger number on top, and subtract the ones column first! No borrowing needed for these!

(Your web app with the 18 questions will go here. The web-app should ideally allow children to see or input numbers in a columnar format.)

Why is Learning Column Subtraction a Great Idea?

• It’s Clear and Organized: Lining up numbers helps you see exactly what you’re subtracting.
• Helps with Bigger Numbers: This method is the start of how you’ll subtract much larger numbers later.
• Builds Accuracy: Following the steps carefully helps you get the right answer.
• Boosts Place Value Skills: It makes you think about tens and ones all the time.

Tips for Grown-Ups: Guiding Column Subtraction Beginners (No Regrouping)

This is the first step into formal written subtraction. The key at this stage is ensuring children understand the setup (alignment, larger number on top) and the process of subtracting column by column, starting with the ones. “No regrouping” means each digit in the top number is greater than or equal to the digit directly below it.

• Correct Alignment is Crucial: Use ‘T’ and ‘O’ headings and squared paper. Ensure the larger number is placed on top for subtraction.
• Subtract Ones First, Then Tens: Consistently work from right to left.
• Language of “Take Away”: Use phrases like “8 take away 5 leaves 3” to reinforce the subtraction concept.
• Check the Top Digit: For these “no regrouping” problems, quickly check with your child that the top digit in each column is bigger than or equal to the bottom one before they start. This builds their awareness for when regrouping will be needed later.
• Relate to Concrete Objects: If needed, briefly model with base-ten blocks, showing the removal of ones blocks, then tens rods, without any need to exchange.