3 ms·
The number of people who can do it quickly in their head, maybe. I don't know a single adult who would look at that problem and say they don't know how to solve
by Retra 11y ago
The number of people who can do it quickly in their head, maybe. I don't know a single adult who would look at that problem and say they don't know how to solve it.
Math is a perishable skill. You get slow at it if you don't use it.
- matwood 11y agoIt is just a matter of remembering the tricks. (9x10) + (9x4)