➖ Two-Digit Subtraction (Tens & Ones)

We’re subtracting like pros — with and without regrouping. Let’s go.

📖 What is Two-Digit Subtraction?

You’re subtracting numbers from 10–99. Each has a tens digit and an ones digit. We subtract ones from ones, tens from tens. If the ones on top are smaller than the ones on bottom, we regroup (a.k.a. “borrow”): break one ten into 10 ones.

Real talk: If ones-place on top is too small, don’t force it — regroup and keep it moving.

🧩 Step-by-Step Examples

No Regrouping

54 − 21

   5 4
 - 2 1
 -----
   3 3
  1. Ones: 4 − 1 = 3
  2. Tens: 5 − 2 = 3
  3. Answer: 33
With Regrouping

63 − 27

   6 3
 - 2 7
 -----
  1. Ones: 3 − 7 ❌ (too small) → borrow 1 ten → 6 tens becomes 5 tens, ones become 13.
  2. Ones now: 13 − 7 = 6
  3. Tens: 5 − 2 = 3
  4. Answer: 36

🧱 Build a Vertical Problem

63
  27
 

✏️ Practice Problems

58 − 23

72 − 48

64 − 39

90 − 54

41 − 17

53 − 28

🔥 Challenge Problems

87 − 69

75 − 58

94 − 37

🧪 Regrouping Lab (Base-Ten Blocks)

See borrowing happen for real: one ten becomes ten ones. Enter any two-digit subtraction (top ≥ bottom).

📉 Number Line Visualizer

Watch backward jumps from the top number down to the answer. Perfect for building the intuition.

🔢 Number Chart (100–1000)

Use the arrows to scroll the chart by 100s.