How to Subtract Two Numbers with Regrouping: GED Math Explained

Understanding Subtraction with Regrouping

• 🎯 The problem involves calculating the change Lucy should receive after buying a shirt for $23 with a $50 bill, which is a subtraction problem: $50 - $23.
• ⚠️ When subtracting numbers column by column, if the top digit is smaller than the bottom digit (e.g., 0 - 3), regrouping is necessary.

The Regrouping Process

• 💡 To regroup, borrow one from the next higher place value to the left. In this case, borrow 1 from the '5' in the tens place.
• ⚡ The '5' becomes a '4', and the borrowed '1' is added to the digit in the ones place, turning the '0' into '10'.

Calculating the Difference

• 🔢 The problem is now 10 - 3 in the ones place, which equals 7.
• ✅ In the tens place, it's 4 - 2, which equals 2.
• 💰 Therefore, the total difference is $27, which is the amount of money Lucy should get back.