Can someone help me with this please

Is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis.

Present age of man is 45 years, 5 years back his age was 4 times age of his son what is present age of his son?

Agrasshopper weighs 0.89 grams. express the grasshopper’s weight in scientific notation.