Length× width× height: so 15×7×3=3 15 cubic centimeter.

Then we look at 630 cubic decimeters. The unit here is cubic decimeter, so we need to convert the unit: 630 cubic decimeter = 630,000 cubic centimeters.

Finally, large volume ÷ small volume = quantity: 630000÷3 15=2000 pieces.

A: Its volume is 3 15 cubic centimeter, and there are 2000 bricks in this pile.