The number of Singapore stamps that Leo had was the 4/3 number of foreign stamps. He gave away 68 Singapore stamps and 12 foreign stamps.
After that, the number of Singapore stamps was 20% of the total number of
stamps he had left. How many Singapore stamps did Leo have in the end?

4/3 as in a improper fraction

the law of definite proportions states samples of a compound will always contain the same proportion of elements by mass. in other words, a given compound will always contain the same elements in the same proportions by mass.the law of multiple proportions states when two elements combine with each other to form more than one compound, then the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers.