Why do you multiply before you add or subtract?

1/2a + (-3a) - 3b - 0.7a

What is the greatest to least - 1, 3/2, 2.5, 0, - 1/2, 2, 0.2

To get there students and chaperones will travel in buses, vans, and cars Buses have 40 seats and cost $300 to rent. Vand have 16 seats and cost $125 to rent. Cars have 5 seats and cost $40 to rent.

Solve by converting fractions to decimals: 8 1/2 = s + 3 1/6

Harry is in line at the store. he has 3 items that cost $5.95,$4.25 and $1.05. explain how Harry can add the cost of the items mentall before the pays for them

A newspaper reporter wants to know how popular the hobby of bird watching is in the city. He asked people at the local bird refuge if they watched birds as a hobby. Which of the following best explains whether the reporters data is valid or not?

I am very confused on how to figure out if y = 3/4x is proportional?

Alison wants to buy a mountain bike for $339.12. If she saves $28.26 each month, in how many months will she be able to buy the bike?

At 12 o'clock the temperature was 7°C. The temperature decreased by - 20°C. What is the new temperature?

Ashleys rentals charges $27.50 per hour to rent a surfboard and a wetsuit. Darlas surf shop charges $23.25 per hour to rent a surfboard plus $17 extra for a wetsuit.