its something for math homework and it confusing!! please help!!!
2007-12-05 13:01:05 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
can you please tell me how to do it?
2007-12-05 13:05:27 · update #1
The answer is: 441
You multiply (calculator, head, multiplication on paper, etc.)
..21
x 21
------
..21
42
------
441
2007-12-05 13:03:53 · answer #1 · answered by Puzzling 7 · 0⤊ 0⤋
21 x 21
= (20 + 1) x (20 + 1)
= 20*20 + 20 + 20 + 1
= 400 + 40 + 1
= 441
2007-12-05 21:05:54 · answer #2 · answered by sv 7 · 0⤊ 0⤋
Hey there!
441. Here's a trick.
21*21-->
21*20+21*1 -->
420+21 -->
441
It's a fundamental use of the Distributive Property.
Hope it helps!
2007-12-05 21:04:02 · answer #3 · answered by ? 6 · 0⤊ 0⤋
21 x 21 =441
2007-12-05 21:03:56 · answer #4 · answered by Anonymous · 0⤊ 0⤋
21*21=21*1=21
=21*20=420
21+ 420=441
2007-12-05 21:06:49 · answer #5 · answered by deannalam555 1 · 0⤊ 0⤋
OMG of course 441
2007-12-05 21:04:31 · answer #6 · answered by horse<3er3226 2 · 0⤊ 0⤋