Volume of Rectangular Prisms for Kids: Length × Width × Height (Grade 5 Math)

Hi, I'm Luna from DoodleBeez. Today we are finding volume. Volume is how much space a solid shape takes up. We measure it by counting how many unit cubes fit inside a shape, like a box.

A unit cube is a cube with every side one unit long. A cube with sides of one centimeter has a volume of one cubic centimeter. We can write that as one centimeter cubed.

Here is a box four cubes long and three cubes wide. The bottom layer holds four times three, which is twelve cubes. The box is two layers high, so twelve times two makes twenty four cubes.

That gives us a shortcut. Volume equals length times width times height. For our box, four times three times two equals twenty four. The volume is twenty four cubic units.

Let's try one with real units. A box is five centimeters long, four centimeters wide and three centimeters high. Five times four is twenty, and twenty times three is sixty. The volume is sixty cubic centimeters.

Here is another way to think about it. Volume equals the area of the base times the height. The base is five by four, so its area is twenty square centimeters. Twenty times three is sixty cubic centimeters.

Now it's your turn. A box is seven centimeters long, two centimeters wide and three centimeters high. What is its volume? Pause and try. Seven times two is fourteen, and fourteen times three is forty two cubic centimeters.

Great job! Remember, volume is the space inside a solid. Multiply length times width times height, and write your answer in cubic units. Practice volume in the Math Lab at doodlebeez.com. See you next time!