Practice problem:
The following is correct?
456 532 1087 + 36 ------ 2132
I will present how to make sure if this calculation is correct; that is, mentally calculate only each last figure:
6 2 7 + 6 ----- 26 + 2 is 8;
In this case where we made sure using each last figure only, we can determine the correctness in a probability percentage of 90.
Practically we can make sure if calculations are correct in our payments, for example, receipts from supermarkets.
Japanese sites Mathematical Formulas| Kodawari House| Pinpoint StreetView| Excel VBA Techniques| Excel Formula Analysis| |