Why not? Because every math system you've ever worked with has obeyed these properties! You have never dealt with a system where a×b did not in fact equal b×a, for instance, or where (a×b)×c did not equal a×(b×c). Which is why the properties probably seem somewhat pointless to you. Don't worry about their "relevance" for now; just make sure you can keep the properties straight so you can pass the next test. The lesson below explains how I kept track of the properties.
Answer:
16.5 is the area
Step-by-step explanation:
The area of the box is equal to 9^3= 729 in^3
729<1000
Final answer: No since the volume of the box is less than the total volume of the cubes
11 blue
2 green
7 brown
total is 20 card
7 out of that 20 are brown
so x out of 100% are brown
7/20=x/100 - cross multiply
700=20x
x=700/20
x=70/2