AI generatedNumberKey Stage 3

Estimating a calculation

Estimating a calculation.

  • Replace awkward values with nearby convenient values.
  • Keep the operation order and check whether the result is a sensible size.

Example 1

Estimate the product by rounding each factor down to a whole number. Is the estimate too high or too low?

EstimateBoth positive factors have been rounded down.
EstimateMaking both positive factors smaller makes the product smaller.
84, an underestimate.

Example 2

Estimate the product by rounding each factor down to a whole number. Is the estimate too high or too low?

EstimateBoth positive factors have been rounded down.
EstimateMaking both positive factors smaller makes the product smaller.
110, an underestimate.

Your turn

Question 1

Estimate the product by rounding each factor down to a whole number. Is the estimate too high or too low?

Check answer
EstimateBoth positive factors have been rounded down.
EstimateMaking both positive factors smaller makes the product smaller.
138, an underestimate.
Question 2

Estimate the product by rounding each factor down to a whole number. Is the estimate too high or too low?

Check answer
EstimateBoth positive factors have been rounded down.
EstimateMaking both positive factors smaller makes the product smaller.
168, an underestimate.
Question 3

Estimate the product by rounding each factor down to a whole number. Is the estimate too high or too low?

Check answer
EstimateBoth positive factors have been rounded down.
EstimateMaking both positive factors smaller makes the product smaller.
200, an underestimate.
Question 4

Estimate the product by rounding each factor down to a whole number. Is the estimate too high or too low?

Check answer
EstimateBoth positive factors have been rounded down.
EstimateMaking both positive factors smaller makes the product smaller.
234, an underestimate.
Question 5

Estimate the product by rounding each factor down to a whole number. Is the estimate too high or too low?

Check answer
EstimateBoth positive factors have been rounded down.
EstimateMaking both positive factors smaller makes the product smaller.
270, an underestimate.
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