Concept 4 of 9
Subtracting 2-Digit Numbers
Today's big idea
Line up the columns, then subtract each one on its own.
58 − 23: ones 8−3=5, tens 5−2=3 → 35.
How it works
👀 What's going on?
58 − 23: stack them and take away column by column.
💡 Here's the trick
Line up the columns, then subtract ones from ones and tens from tens.
58 − 23: ones 8 − 3 = 5, tens 5 − 2 = 3. The answer is 35.
✍️ Try it
76 − 42: ones 6 − 2 = 4, tens 7 − 4 = 3. → 34.
⚠️ Watch out
Take the bottom digit away from the top digit, not the other way round.
Watch me solve one
Quanta solves it
“Watch how I think through one of these — then you try.”
THE PROBLEM
“What is 67 − 24?”
- 1
Subtract the ones
7 − 4 = 3.
- 2
Subtract the tens
6 − 2 = 4.
- 3
Answer ✓
67 − 24 = 43
Now you try one — same steps, different story 👇
See it in action
⚡ Time to play!
Subtract the ones column.
58 − 23
8 − 3 = ?
Quick check
✅ VERIFICATION
What is 89 − 35?
⚡ Finish the activity above first to answer.
Keep going!
Up next: Adding with Carrying
Ten ones become one ten, carried over.