4. which strategies can be used to solve this problem?

a company delivered 1,800 gallons of milk per month in march, april, and may. it delivered 2,100 gallons per month in june and july. how many gallons of milk did the company deliver altogether in the five months?

choose all answers that are correct.

a.
translate into an equation.
5 × (1,800 + 2,100) = n

b.
use logical reasoning.
think that the company delivered 1,800 gallons for each of 3 months (3 × 1,800) and 2,100 gallons for each of 2 months (2 × 2,100). adding the two products gives the amount delivered in 5 months.

c.
draw a diagram.
draw 3 circles and write 1,800 in each. draw 2 circles and write 2,100 in each. add the 5 amounts to get the total delivered in 5 months.

d.
work backward.
start with 2,100 and add it to 1,800 to get 3,900. multiply the sum by 5 to get the total amount delivered in 5 months.