#color(blue)("Dealing with a lot of those zeros")#
What follows is where the shortcut of cancelling comes from.
#72000 -> 72xx1000#
#4900000-> 4900xx1000#
#(72xx1000)/(4900xx1000)" "=" "72/4900xx1000/1000#
But #1000/1000=1# and anything multiplied by 1 does not change its value.
#72/4900xx1000/1000" "=" "72/4900xx1" "=" "72/4900#
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#color(blue)("Dealing with what is left")#
#72/4900" "=" "(72-:8)/(49000-:8) = 9/6125#
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#color(blue)("This is one way to find a common factor - there are other methods")#
Observe that the highest #ul("common")# factor is #2xx2xx2=8#
