First, make all the denominators the same.
In this case, all the denominators are of the value of either 4 or 5. So, now what is the biggest number we can multiply by, using four AND five.
Answer is 20 because 5*4 is 20 and 4*5 is 20.
So now for all the ingredients, we have to :
-multiply the whole fraction by 4 if the denominator is 5
- Multiply the whole fraction by 5 if the denominator is 4
So for sugar, you would do 3/4 ( times 3 by 5, times 4 by 5)
Which is 15/20
For cinnamon, you would do 2/5 ( times 2 by 4, times 5 by 4)
Which is 8/20
For flour, you would do 4/5 ( times 4 by 4, times 5 by 4)
Which is 16/20
But, for your problem, you need to work out how much the baker has left over after using 1/5 of pound of all the ingredients. So, you would do 1/5 ( times 1 by 4, times 5 by 4)
Which is 4/20
Now, we can subtract it by the ingredients For sugar:
15/20 - 4/20
Now the baker has 11/20 pound of sugar
For cinnamon:
8/20 - 4/20
Now the baker has 4/20 pound of cinnamon ( simplified fraction is 1/5)
For flour
16/20 - 4/20
Now the baker has 12/20 pound of flour ( simplified fraction is 3/5)
Hope this helps;)
