Kiddie Blocks PH
Tutorial Center • Project 8, Quezon City
Long Division Mastery & Fluency
DMSB Algorithm, Estimation & Place Value Regrouping
Grade 4 • Math
Page 1 of 4
📌 The 4-Step Long Division Cycle: DMSB
Remember: Does McDonald's Serve Burgers? (Divide → Multiply → Subtract → Bring Down → Repeat or Remainder).
1437 r 1
┌──────
4 │ 5749
- 4
───
17
- 16
────
14
- 12
────
29
- 28
────
1
• Step 1 (Thousands): 5 ÷ 4 = 1. Multiply: 1 × 4 = 4. Subtract: 5 - 4 = 1. Bring down 7 → 17.
• Step 2 (Hundreds): 17 ÷ 4 = 4. Multiply: 4 × 4 = 16. Subtract: 17 - 16 = 1. Bring down 4 → 14.
• Step 3 (Tens): 14 ÷ 4 = 3. Multiply: 3 × 4 = 12. Subtract: 14 - 12 = 2. Bring down 9 → 29.
• Step 4 (Ones): 29 ÷ 4 = 7. Multiply: 7 × 4 = 28. Subtract: 29 - 28 = 1 (Remainder).
• Check: (Quotient × Divisor) + Remainder = (1,437 × 4) + 1 = 5,748 + 1 = 5,749 ✔️
• Step 2 (Hundreds): 17 ÷ 4 = 4. Multiply: 4 × 4 = 16. Subtract: 17 - 16 = 1. Bring down 4 → 14.
• Step 3 (Tens): 14 ÷ 4 = 3. Multiply: 3 × 4 = 12. Subtract: 14 - 12 = 2. Bring down 9 → 29.
• Step 4 (Ones): 29 ÷ 4 = 7. Multiply: 7 × 4 = 28. Subtract: 29 - 28 = 1 (Remainder).
• Check: (Quotient × Divisor) + Remainder = (1,437 × 4) + 1 = 5,748 + 1 = 5,749 ✔️
📌 Skill 2: Dividing by 2-Digit Numbers using Compatible Estimation
To divide by a 2-digit number (like 26), round the divisor to the nearest 10 (26 rounds to 30) to estimate each quotient digit quickly!
33 r 16
┌─────
26 │ 874
- 78
────
94
- 78
────
16
• Estimate Digit 1: 26 doesn't fit into 8. Look at 87. Round 26 to 30. How many 30s in 87? About 3. Test: 3 × 26 = 78. Subtract: 87 - 78 = 9. Bring down 4 → 94.
• Estimate Digit 2: How many 30s in 94? About 3. Test: 3 × 26 = 78. Subtract: 94 - 78 = 16.
• Remainder Check: 16 is less than 26 (R < D). Quotient = 33 r 16.
• Check: (33 × 26) + 16 = 858 + 16 = 874 ✔️
• Estimate Digit 2: How many 30s in 94? About 3. Test: 3 × 26 = 78. Subtract: 94 - 78 = 16.
• Remainder Check: 16 is less than 26 (R < D). Quotient = 33 r 16.
• Check: (33 × 26) + 16 = 858 + 16 = 874 ✔️
⚡ Long Division Golden Rules:
1. Remainder Rule: The remainder must ALWAYS be strictly less than the divisor (R < D). If R ≥ D, your quotient digit was too small!
2. Don't Forget the Zero in Quotients: If a divisor does not go into a brought-down number (e.g., 3 ÷ 8 = 0), you MUST write a 0 in the quotient before bringing down the next digit!
1. Remainder Rule: The remainder must ALWAYS be strictly less than the divisor (R < D). If R ≥ D, your quotient digit was too small!
2. Don't Forget the Zero in Quotients: If a divisor does not go into a brought-down number (e.g., 3 ÷ 8 = 0), you MUST write a 0 in the quotient before bringing down the next digit!