Chalky Ball

Imagine you have a classmate Peter, and it is rather hard to observe his height with bare eyes. But when you are standing right next to him, you know you are approximately 5cm shorter than him. Because knowing you are…

Algebra is a type of math that uses letters and symbols to represent numbers and quantities. Instead of just using numbers, we use letters like abc or xyz to stand for unknown values that we want to figure out. For…