Magnitude Estimates
- A Magnitude Estimate is a very rough estimate
that answers the question:
Is
the solution in 1s? 10s? 1,000s ? 10,000s? - How to make a magnitude estimate:
1.
Round the numbers to the nearest 1, or 10, or 100, etc. 2.
Make the calculation. 3.
Determine if the solution is in 1s, 10s, 100, 1,000s, etc. - For example:
Make
a magnitude estimate for 356 * 17: 1.
Round the 356 to the nearest 100: 400. 2.
Round the 17 to the nearest 10: 20. 3.
Multiply the estimates: 400 * 20 =
8,000 4.
The solution of 356 * 17 is in the 1,000s. 5.
To check, the actual solution is: 6,052 - Another example:
Make
a magnitude estimate for 24.8 * .7: 1.
Round the 24.8 to the nearest 10: 25 2.
Round the .7 to the nearest 1: 1 3.
Multiply the estimates: 25 * 1 = 25 4.
The solution of 24.8 * .7 is in the 10s. 5.
To check, the actual solution is: 17.36 |