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Mental math 5×395=5×(_ - _)

User Brivvirs
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2 Answers

1 vote
5× 390-5
i am not sure, just my guess !!!
User Olly Hodgson
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2 votes

To mentally compute
\(5 * 395\) using the distributive property:
\[5 * 395 = 5 * (400 - 5) = 5 * 400 - 5 * 5 = 2000 - 25 = 1975\]

To mentally calculate
\(5 * 395\), one can employ the distributive property by decomposing 395 into a more manageable form. Breaking it down as
\(400 - 5\), the multiplication becomes
\(5 * 400 - 5 * 5\), resulting in
\(2000 - 25\).

Combining these values,
\(5 * 395\) equals 1975.

This method simplifies the computation by using the more rounded number 400, reducing the mental burden of multiplying by 395 directly. This mental math approach leverages the simplicity of operations with multiples of 5 and 10 to arrive at a quick and accurate result.

User Dbotha
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