Please help i can't figure it out​

What is the number 321,000,000 in scientific notation? also what is the number? ?

Carlos spent 1 1/4 hours doing his math homework he spent 1/4 of his time practicing his multiplication facts how many hours to carlos been practicing his multiplication facts

Consider an example of a deck of 52 cards: example set of 52 playing cards: 13 of each suit clubs, diamonds, hearts, and spades ace 2 3 4 5 6 7 8 9 10 jack queen king clubs diamonds hearts spades what is the probability of drawing three queens from a standard deck of cards, given that the first card drawn was a queen? assume that the cards are not replaced.