There are 8 songs that you want to buy but you only can buy 3 of the songs. how many different groups of songs can you buy

An unknown number of kids and buses are getting assigned. when assigning 4 kids to each bus, there are 2 kids that aren't placed in a bus. when assigning 8 kids to each bus, there are 2 empty buses. how many total kids are there?

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

Find the distance between (7,-6) and (-3,-9)