How do you evaluate #710,000\times \frac { 15} { 16} #?

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Answer 1 · 2016-12-17T09:12:22

#= 665,625#

There are some facts in maths are useful to know.
When working with fractions and decimals, powers of 2, 5 and 10 are easy to relate to each other.

Note the following:

#2 xx 5 = 10#

#4 xx 25 = 100" "rarr" "2^2 xx 5^2 = 10^2#

#8 xx 125 = 1000" "rarr " "2^3 xx 5^3 = 10^3#

#16 xx 625 = 10,000" "rarr" "2^4 xx 5^4 = 10^4#

#710,000 xx 15/16 = (71 xx 10,000)/1 xx 15/16#

#=(71 xx cancel(10,000)^625)/1 xx 15/16#

#= color(red)(71) xx 625 xx color(red)(3) xx 5#

#=color(red)(213) xx 3125#

#=(color(red)(200+10+3)) xx 3125" "larr# distributive law

#= 625,000 + 31,250 + 9,375#

#= 665,625#