How many times smaller is 2×10 to the -5th than 4×10 to the -3rd
HELP M

Which inequality comparing two of the expressions is true when 0.7 < x < 0.9

Evaluate the expression for the given value of the variable 7a - 4a for a =8

Mrs. morton has a special reward system for her class. when all her students behave well, she rewards them by putting 3 marbles into a marble jar. when the jar has 100 or more marbles, the students have a party. right now, the the jar has 24 marbles. how could mrs. morton reward the class in order for the students to have a party?