Two-Digit Subtraction With Regrouping

Sometimes when you are subtracting two-digit numbers, the digit on the top is smaller than the digit on the bottom. When this happens, you don't have enough to subtract, so you need to regroup (also called borrowing).

Regrouping means taking $1$ ten from the tens place and trading it for $10$ ones.

How to Regroup

Let's solve $53 - 28$:

Step 1: Look at the ones place. We need to subtract $8$ from $3$ ($3 - 8$). Since $3$ is smaller than $8$, we don't have enough! We need to regroup.

Step 2: Borrow from the tens place. Go to the tens place in $53$. Cross out the $5$ tens and make it $4$ tens. Give that $1$ ten (which is exactly $10$ ones) to the ones place. Now, the $3$ becomes $13$ ($10 + 3$).

Step 3: Subtract the ones. Now you have enough to subtract the ones: $13 - 8 = 5$

Step 4: Subtract the tens. Next, subtract the tens. Remember, we only have $4$ tens left on top! $4 - 2 = 2$

Put it all together, and the answer is $25$! So, $53 - 28 = 25$.

More Examples

Let's try a couple more problems to practice borrowing.

Example 1: $72 - 45$

• Ones place: $2 - 5$. We can't do that, so we borrow $1$ ten from the $7$. The $7$ becomes a $6$, and the $2$ becomes $12$.
• Subtract ones: $12 - 5 = 7$.
• Subtract tens: $6 - 4 = 2$.
• Answer: $27$

Example 2: $91 - 36$

• Ones place: $1 - 6$. Borrow $1$ ten from the $9$. The $9$ becomes an $8$, and the $1$ becomes $11$.
• Subtract ones: $11 - 6 = 5$.
• Subtract tens: $8 - 3 = 5$.
• Answer: $55$