It’s a blast to make things out of Lego, like castles, cars and robots. Well, as we see in this video, someone built a Lego robot that *builds* Lego cars itself! The robot factory grabs the body of the car, then grabs a steering wheel and presses it on. Then it sticks on the front hood, the back seat, and other bricks. In the end, out pops a car that looks exactly like the last 8-10 cars made. It takes a minute or more to stick on each piece, so you could build a car much faster than the robot. But if it’s bedtime and you need 100 cars made by tomorrow, this robot could do the job for you.

*Wee ones:* If the Lego car starts with 4 wheels and a floor, how many pieces does the car have?

*Little kids:* If every car needs 2 pairs of wheels, how many pairs do 3 cars use in total? *Bonus:* If you have 10 pairs in stock, how many cars can you make?

*Big kids:* If right now the robot makes 1 car every 30 minutes, how fast would it make a car if it made them twice as fast? *Bonus:* At the new speed, how many can it crank out in 1 hour? (*Reminder if needed:* An hour has 60 minutes.)

*The sky’s the limit:* Without multiplying it all out, can you tell who will finish first: a robot building 28 cars spending 6 minutes on each, or a robot building 50 cars spending 3 minutes on each?

Answers:

*Wee ones:* 5 pieces.

*Little kids:* 6 pairs of wheels. *Bonus:* 5 cars.

*Big kids:* 1 every 15 minutes. *Bonus:* 4 cars per hour.

*The sky’s the limit:* The 2nd robot will finish first. It’s making fewer than double the cars, but at exactly twice the speed. If you *did* multiply it all out, you’d get 28 x 6 = 168 minutes for the 1st robot, and 50 x 3 = 150 minutes for the 2nd.