IN AWE
I'm surounded by assholes
- Joined
- Dec 20, 2007
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Real quick add 170 and 220 in your head......
Another way is to add 200 plus 200 and subtract 10. Numbers greater than 5 you base up and subtract, numbers lower than 5 you base down and add. It is easier to add and subtract small numbers in one's head than large numbers so base 10 turns it all into small numbers.
It is how I was taught in the mid and late 60's math before calculators. It makes it easier to add big numbers like 10,465 plus 62,982 in your head without pencil and paper.
Or add 70 + 20 + 300, or ????? My point being that there is no "right" way now, that it is open to interpretation. In the 70's we had to "show our math".
Correct answer is, I don't care how you get it. This is how you right it.
170
+220
----------- or 170 + 220 = 390
390