How do you multiply $2(6+10)$ ?

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Answer 1 · 2016-05-08T16:36:55

32

$color(blue)("Shortcut method")$

$2xx16=32$

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$color(blue)("Teaching bit:")$

suppose you had $2(a+b)$

This is 2 lots of $(a+b)$

So $2(a+b)" "->" "(a+b)+(a+b)$

Which is: $a+a+b+b = 2a+2b$

From this you can observe that you get the same answer if you just multiply everything inside the brackets by 2.

Suppose you had $=-3(a+b) = -3a-3b$

Suppose you had $-3(a-4b) = -3a+12b$

Suppose you had $5(1/(5a)+b/10) =5/(5a)+(5b)/10= 1/a+b/2$

How do you multiply 2(6+10)2(6+10)?