Ter. Identify the property used in this equation:
(-2) + 6 + 1 = 1 + 6 + (-2)
Use the interactive tool tahyaluate the expression.

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?