Plz me

adam has $450. he spends $210 on food. later he divides all his money into four parts out of which three parts were distributed and one part he kept for himself. then he found $50 on the road.

write the final expression and find the money he has left.

Which approach to the theory-and-research cycle does the following sequence reflect: (1) specific observations suggest generalizations, (2) generalizations produce a tentative theory, (3) the theory is tested through the formation of hypotheses, and (4) hypotheses may provide suggestions for additional observations?