Addition is a fundamental mathematical operation where two or more numbers are combined to find their total or sum. We have already seen an example on page 2. Another example of 1-digit addition (which we'll get to in a few minutes) is: 1+3 = 4 or 9 + 3 = 12. As you can see, you can add 1+3 (1,2,3,4) and 3+1 (3,4) to get the same answer. This is because addition is commutative.
Hello, Martha.
Don't mind her, but you cannot ignore Presia — her sister. Watch out for who you pay attention to — don't get them mixed up! (You'll see the differences later). Anyway. Back to the definition of commutative.
The operations addition and multiplication are commutative. Division and subtraction are not commutative, because you cannot switch the minuend and the subtrahend, or the divisor and the dividend.
Because we can take any 2 numbers — say, like 2 and 3 — and do this...
3 - 2 = 1 2 - 3 = (-1)
You see? The differences are different. 1 ≠ -1. Also note that I put parentheses around the -1 so you wouldn't get confused with the = and the -. Sometimes you kittens just get them mixed up and think it's part of the equation.
Now you probably understand already. You can switch the addends and get the same answer, or switch the products and get the same answer. 
You bet! Here goes...
2+3=5 3+2=5 3×4=12 4×3=12
That was rather exciting, because we got to prove that it worked for addition and multiplication, and also got to show everybody that subtraction did not work. 
Right. Division. Let's show everybody another example of division...
72 ÷ 8 = 9 72 ÷ 9 = 8
See? The quotients are different. 
Yes, they are. But not to everybody. 
You actually might want to move over because...
Yep. All of your friends are here to meet you. All of our EFM Characters!