Basic mathematics

Refer the following table, where in the first column four pairs of two vectors are shown and in the second column some possible outcomes of basic mathematical operation on these vectors are given. Suggest suitable match(s).

In a school there are 20 teachers who teach mathematics or physics.Of these,12 teach mathematics and 4 teach both physics and mathematics.How many teach physics?

72% of 25 students are good in mathematics. How many are not good in mathematics?

In a class of 35 students , 17 have taken Mathematics , 10 have taken mathematics but not economics if each student has taken either mathematics OR Economics or both , then the number of students who have taken Economics but not mathematics is

In a class of 100 students 90 have taken mathematics 70 have taken mathematics but not biology. Find the number of students who have taken biology but not mathematics. Each student has taken either mathematics or biology or both.