Grade 3 Subtraction: Borrowing Across Zeros

Handle borrowing when there are zeros

What You'll Learn

Borrow when tens digit is 0
Chain borrowing across zeros
Apply careful checking

📖Zeros Are Tricky

When you need to borrow but the next digit is 0, you must borrow from the digit after that. 500 - 137: Borrow from hundreds, making it 4 hundreds and 10 tens. Then borrow from tens to ones.

💡

When borrowing across a zero, the zero becomes 9 (because you borrowed 1 from it too)!

Worked examples

Real problems from the practice worksheets, solved one step at a time.

Example 1
300 − 49 = ?
1. Line up the numbers by place value and subtract each column from right to left.
2. Ones: 0 is less than 9, so borrow 1 from the tens: 10 − 9 = 1.
3. Tens: 0 has nothing to lend, so it borrows 1 from the hundreds and becomes 10, then lends 1 to the ones, leaving 9. 9 − 4 = 5.
4. Hundreds: 3 lent 1, so it is now 2. 2 − 0 = 2.
5. 300 − 49 = 251
Answer: 251
Example 2
900 − 431 = ?
1. Line up the numbers by place value and subtract each column from right to left.
2. Ones: 0 is less than 1, so borrow 1 from the tens: 10 − 1 = 9.
3. Tens: 0 has nothing to lend, so it borrows 1 from the hundreds and becomes 10, then lends 1 to the ones, leaving 9. 9 − 3 = 6.
4. Hundreds: 9 lent 1, so it is now 8. 8 − 4 = 4.
5. 900 − 431 = 469
Answer: 469
Example 3
302 − 13 = ?
1. Line up the numbers by place value and subtract each column from right to left.
2. Ones: 2 is less than 3, so borrow 1 from the tens: 12 − 3 = 9.
3. Tens: 0 has nothing to lend, so it borrows 1 from the hundreds and becomes 10, then lends 1 to the ones, leaving 9. 9 − 1 = 8.
4. Hundreds: 3 lent 1, so it is now 2. 2 − 0 = 2.
5. 302 − 13 = 289
Answer: 289