John is cooking cupcakes. the recipe calls for 3 3/10 cups of flour. He accidentally put 3 5/8 cups. How many cups did he add?
To solve this problem, we need to subtract the correct amount of flour from the amount John actually put.
The correct amount of flour is 3 3/10 cups.
To convert the mixed number to an improper fraction, we multiply the whole number (3) by the denominator (10) and add the numerator (3) to get 33/10.
John put 3 5/8 cups of flour.
To convert the mixed number to an improper fraction, we multiply the whole number (3) by the denominator (8) and add the numerator (5) to get 29/8.
Now we can subtract: 29/8 - 33/10.
To subtract fractions with different denominators, we need to find the least common multiple (LCM) of the denominators (8 and 10), which is 40.
Next, we convert the fractions to have a common denominator of 40.
(29/8) x (5/5) = 145/40
(33/10) x (4/4) = 132/40
Now we can subtract: 145/40 - 132/40 = 13/40
Therefore, John added 13/40 cups of flour by mistake.