Abbott And Costello demonstrate how Common Core Math works from this funny scene of “In The Navy” that was filmed in 1941. It’s amazing that we didn’t start teaching Common Core Math to our kids earlier as you can see how easy it is to do. 13 x 7 really is 28 because after all the steps clearly show that to be the case. If you’re not familiar with Common Core Math find a kid in elementary school or middle school and see if you can do their math homework according to the rules they are being taught.