tfarrejfm
Stage 15 of 20

Multiplication: 1, 2, 5, and 10

Before tackling harder tables, learn the patterns behind multiplying by 1, 2, 5, and 10. These facts appear everywhere and unlock quick mental calculations.

What You'll Learn

  • Multiply any number by 1, 2, 5, and 10 instantly
  • Recognize the halving and doubling connection (×2 and ÷2)
  • Use ×10 for place value shifts and ×5 as half of ×10

Explanation

Multiplying by 10 shifts every digit one place left: 34 × 10 = 340. The zero fills the ones place.

Multiplying by 2 is doubling — you already practiced this in Stage 6. 7 × 2 = 14 because 7 + 7 = 14.

Multiplying by 5: take half and multiply by 10 (or multiply by 10 and halve). 24 × 5 = 120 because 24 × 10 = 240, halved = 120.

Multiplying by 1 changes nothing. Use it to verify: if 8 × 5 = 40, then 40 × 1 = 40.

Pro Tips

  • • For ×5, think "half of ×10" — it works for even and odd numbers.
  • • Count by 5s (5, 10, 15…) to internalize the rhythm.
  • • Connect ×2 facts to your doubles from Stage 6.

Practice Exercises

Work through each problem mentally. Click "Show Answer" when you're ready to check.

  1. 1. 7 × 2 = ?
  2. 2. 8 × 5 = ?
  3. 3. 6 × 10 = ?
  4. 4. 9 × 2 = ?
  5. 5. 4 × 5 = ?
  6. 6. 12 × 10 = ?
  7. 7. 11 × 2 = ?
  8. 8. 15 × 5 = ?
  9. 9. 3 × 10 = ?
  10. 10. 20 × 5 = ?