Estimate products – multiply by larger numbers

Understanding Estimation

• Definition: Estimation is finding an approximate value rather than an exact number.
• Purpose: Helps in making quick calculations and understanding if an answer is reasonable.

Rounding Numbers

• Rounding: To simplify multiplication, round numbers to the nearest ten, hundred, or thousand.
• Examples:
  • Round 48 to 50: For 48 × 6, estimate 50 × 6 = 300.
  • Round 235 to 200: For 235 × 4, estimate 200 × 4 = 800.

Using Compatible Numbers

• Definition: Numbers that are easy to multiply mentally.
• Examples:
  • Round 49 to 50 and 8 to 10: For 49 × 8, estimate 50 × 10 = 500.

Basic Multiplication Strategies

• Break Down Numbers: Use smaller, easier-to-multiply numbers.
  • Example: For 27 × 8, break it into (20 × 8) + (7 × 8) = 160 + 56 = 216.
• Use Multiples of 10: If multiplying by 10, 20, etc., adjust the numbers accordingly.
  • Example: For 32 × 20, estimate 30 × 20 = 600.

Estimating Products

• Check Reasonableness: After estimating, compare with the actual product to see if it makes sense.
• Examples:
  • For 58 × 9: Estimate 60 × 10 = 600.
  • For 134 × 5: Estimate 130 × 5 = 650.

Learn with an example

Let’s practice!🖊️