Subtraction with Regrouping

In this lesson, we will learn how to perform subtraction when we need to regroup. This occurs when the top number in a column is smaller than the bottom number.

Steps for Subtraction with Regrouping:

1. Align the numbers vertically by place value (ones, tens, hundreds, etc.).
2. Start from the rightmost column (the ones). If the top number is smaller, regroup from the next column.
3. Subtract the numbers in each column, moving left.

Example:

Let's solve the problem: 53 - 28.

1. Align the numbers:

   $$\begin{array}{rr} & 5 & 3 \\ - & 2 & 8 \\ \end{array}$$

So, we find:

$$53 - 28 = 25$$

Key Questions:

• What do you do if the top number is smaller than the bottom number in a column?
• How do you know when to regroup?
• Can you explain why we have to borrow when regrouping?

Keywords:

• Regrouping
• Borrowing
• Subtraction
• Place Value
• Ones
• Tens