3 ms·
The addition is simple. As soon as you tell someone that 62 * 20 is the same as 60 * 20 + 2 * 20, you lose them. Try it out and see for yourself.
by linuxftw 6y ago
The addition is simple. As soon as you tell someone that 62 * 20 is the same as 60 * 20 + 2 * 20, you lose them. Try it out and see for yourself.
- sfink 6y agoNot if you draw the picture. A rectangle with height divided into 60 and 2, width 20. Then it's obvious the total area is the sum of the two parts. My kids got very comfortable early on with that notation. Switching to the standard algorithm was tough, even after they understood why it was equivalent, because the diagram just makes so much more sense.
- dorchadas 6y agoOr you could even just build it up from basics, which is how I would expect it to be done. It's clear that 220 is the same as 120+120, then you can show that 320 = 220+120, etc etc. If they learn it that way at first, it should be clear to them that (60+2)(20) = 6020+220.