Half Squares Pretty tricks for
doing mental arithmetic are often useful. Here is one that is particularly nice. The Problems: You probably know
that 5 x 6 = 30… Now calculate 5.5 x 5.5
( or 5.5^{2} ) on a calculator. Can you see the connection? Try 2.5^{2}^{
} (close to 2 x
3),
7.5^{2} and
19.5^{2} as well, to check your
method. Can you see how the
diagram below explains why the method works ?
Can you now see how to
simply write down:
25^{2
}, 75^{2}
and 195^{2}
as well?
Open the File as a Word Document

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