Solve Vertical Subtraction: 98 minus 79 Step-by-Step

Q: What does 'regrouping' or 'borrowing' actually mean?

Regrouping means taking 1 ten from the tens place and converting it to 10 ones. So 98 becomes 8 tens and 18 ones instead of 9 tens and 8 ones.

Q: Why can't I just subtract 8 - 9 = 1?

Because 8 is smaller than 9! You can't take away 9 things when you only have 8. That's why we need to borrow from the tens column first.

Q: How do I remember which number goes on top?

The larger number (98) always goes on top because it's the minuend - the number we're subtracting from. The smaller number (79) is the subtrahend below.

Q: What if I need to borrow from a zero?

You'll need to keep borrowing leftward until you find a non-zero digit. Each zero becomes 9, and the non-zero digit decreases by 1.

Q: How can I check if my answer is right?

Use addition to check: $ 19 + 79 = 98 $. If your answer plus the bottom number equals the top number, you're correct!

Vertical Subtraction with Regrouping

$\begin{aligned} &98 \\ -& \\ &79 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations

00:00 Solve

00:03 Each time we consider a shortage of 2 digits, and then we place

00:06 8 is less than 9

00:09 Therefore we borrow 1 from tens, and add this amount to ones

00:13 So now instead of 8 we will have 18

00:17 We subtract the ones from ones plus the ten

00:21 Place in ones

00:24 Subtract tens from tens, and place in tens

00:27 And this is the solution to the question

Step-by-step written solution

Follow each step carefully to understand the complete solution

Understand the problem

$\begin{aligned} &98 \\ -& \\ &79 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

Step-by-step solution

To solve this problem, we'll subtract the two-digit numbers using the vertical subtraction method:

Step 1: Set up the problem vertically with minuend (98) above the subtrahend (79). Ensure digits are aligned by place value.
Step 2: Begin subtracting from the right-most column, the units place (8 - 9). Since 8 is less than 9, we must regroup.
Step 3: Regroup by borrowing 1 ten from the tens place of 98. This changes the tens place from 9 to 8, and the ones place becomes 18.
Step 4: Subtract the units column: $18 - 9 = 9$ .
Step 5: Now subtract the tens place digit. After borrowing, the tens digit of 98 is 8. Subtract: $8 - 7 = 1$ .

Combining the results from the two columns, we find that $98 - 79 = 19$ .

Therefore, the solution to the problem is $19$ .

Final Answer

Key Points to Remember

Essential concepts to master this topic

Alignment: Stack numbers with units and tens columns properly aligned
Regrouping: When 8 < 9, borrow 1 ten making 18 - 9 = 9
Verification: Add your answer to subtrahend: 19 + 79 = 98 ✓

Common Mistakes

Avoid these frequent errors

Subtracting smaller from larger digit regardless of position
Don't subtract 8 - 9 = 1 by switching to 9 - 8 = wrong answer of 21! This ignores place value and regrouping rules. Always regroup by borrowing from the next column when the top digit is smaller.

Practice Quiz

Test your knowledge with interactive questions

$\begin{aligned} &105 \\ -& \\ &~~~~3 \\ &\underline{\phantom{776}} & \\ \end{aligned}$

FAQ

Everything you need to know about this question

What does 'regrouping' or 'borrowing' actually mean?

Regrouping means taking 1 ten from the tens place and converting it to 10 ones. So 98 becomes 8 tens and 18 ones instead of 9 tens and 8 ones.

Why can't I just subtract 8 - 9 = 1?

Because 8 is smaller than 9! You can't take away 9 things when you only have 8. That's why we need to borrow from the tens column first.

How do I remember which number goes on top?

The larger number (98) always goes on top because it's the minuend - the number we're subtracting from. The smaller number (79) is the subtrahend below.

What if I need to borrow from a zero?

You'll need to keep borrowing leftward until you find a non-zero digit. Each zero becomes 9, and the non-zero digit decreases by 1.

How can I check if my answer is right?

Use addition to check: $19 + 79 = 98$ . If your answer plus the bottom number equals the top number, you're correct!

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