Lets say a books of searl cost sorry not te best at spelling
1 cost 2.99 for 60g
2 cost 3.99 for 80g
3 cost 4.99 for 100 g
how do find whats the best cost for a box of seral
lets put it to a fraction
60 1
---- = -------
2.99 x we put x because its the unknown number if you wanted to you could put abcd or even e
we want to find out how much 1 g cost so we put 16 on the top with the other 60 g
make the butter fly 2.99x1=60x
2.99x1=2.99
now
2.99=60x draw the line down the equl change it to devide (EVERY TIME THE NUMBER IS NEXT TO THE LETTER ITS DEVIDE)
ok so both side devide then we put the 60 down what ever you do to one side you do to the other so cross out the 60 on the right now its just
2.99
----------
60
thats 0.0498 or somthing its more numbers but you round up and so one till you find with has less for more ull find out 100g for 4.99 is best and thats how you make a fraction