John raises butterflies.  He has 4 jars of 10 caterpillars each.  40% of them fail to become butterflies, but the rest become caterpillars.    He sells the butterflies for $3 each.  How much money does he make?
He has 4*10=<T>multiply(4, 10)=40 caterpillars.
40*.4=<T>multiply(40, 0.4)=16.0 fail to form.
That means he has 40-16=<T>subtract(40, 16)=24 butterflies.
So he makes 24*3=$<T>multiply(24, 3)=72
