Add and subtract the values. Express your answer in scientific notation. (6.15x 10^8)-(2.5x 10^7)+(3.4 x 10^9)
6.24 x 10^8
7.05x 10^8
3.99 x 10^9
4.04 x 10^9

Cameron made 1 loaf of bread. his family ate 4/6 of the loaf of bread. how much of the loaf of bread remains? /

Simplify the expression. -2/5(10+15m-20n)

The u-drive rent-a-truck company plans to spend $13 million on 320 new vehicles. each commercial van will cost $25 comma 000, each small truck $50 comma 000, and each large truck  $80 comma 000. past experience shows that they need twice as many vans as small trucks. how many of each type of vehicle can they buy?