Chris has 4 rocks that each weigh 12 kilograms. He keeps them in a box that weighs 6 kilograms. He can lift all of the rocks in the box above his head at once. Estimate how many kilograms Chris can lift above his head.
if each rock weighs 12 kilo and there are 4, you multiply 4 and 12. Then you add the other six that he lifted above his head that is the box. You should get 54
