The boxes checked are right
a) true: In some instances, an irrational number can be added to an irrational number to become rational, but adding a rational number to one will not work
b) false: It only sometimes works
c) true: e.g. square roots --> (√5)² = 5
d) true: a rational number multiplied by any rational number will be rational
e) false: e.g. perfect squares --> √64 = 8
f) true: e.g. √(5/3) = (√5)/(√3) = (√5*√3)/3
