color(red)("This is much faster if you have memorised that "5xx7=35")
color(blue)("Dealing with the negative and positive")
When multiplying or dividing, if the signs are the same then the answer is positive. If they the signs are not the same then the answer is negative.
We have (+35) -:(-7)
The signs are not the same so the answer is negative.
So now we have " "-(35-:7)
Write as " "-(35-:7) ->(-35/7)
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color(blue)("Shortcut method")
color(red)("If you can do it this is the most efficient way."
color(red)("You jump steps by pulling this from memory")
Known 5xx7=35
" "color(brown)(ul(bar(|color(white)(2/2)35-:(-7)=-5" "|)))
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~~~~~~~~~~ color(purple)("Now we do it the hard way! ")~~~~~~~~~~~~~~~~~
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Observe that " "35->3.5=1/2xx7
If the above condition is true then the factors of 35 are 5 and 7
color(blue)("Dealing with the numbers")
7 is a factor of both 7 and 35 so divide top and bottom by 7
-35/7" "=" "- (35-:7)/(7-:7) " "=" "-5/1 = -5
" "color(brown)(ul(bar(|color(white)(2/2)35-:(-7)=-5" "|)))
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color(blue)("Footnote interesting fact for comparison")
3xx5=15" "->" "1/2xx3=1.5 larr" same digits"
4xx5=20" "->" "1/2xx4=2 larr" same digit but with 0"
5xx5=25" "->" "1/2xx5=2.5 larr" same digits"
6xx5=30" "->" "1/2xx6=3 larr" same digit but with 0"
and so on
