Commutative Law of Multiplication. Created by Sal Khan and Monterey Institute for Technology and Education.
Use the commutative law of multiplication to write 2 times 34 in a different way. Simplify both expressions to show that they have identical results. So once again, this commutative law just means that order doesn't matter. It sounds very fancy. Commutative law of multiplication. But all that says is that it doesn't matter whether we do 2 times 34 or whether we do 34 times 2. The order does not matter. We can commute the two terms. Both of these are going to get you the same exact answer. So let's try it out. What is 2 times 34? And we could write it like this, literally. You'll almost never see it written like this, but it is literally 2 times 34. Almost always people write the larger digit on top, or the digit with more digits, or the number with more digits on top. But let's do it this way. 4 times 2 is 8, and then we'll put a 0. 3 times 2 is 6, or you can view it as 30 times 2 is 60. Add them together. 8 plus 0 is 8. 6, bring it down. It's not being added to anything. You get 68. So 2 times 34 is 68. Now, if you do 34 times 2, 2 times 4 is 8, 2 times 3 is 6. That's why it's always nicer to write the number with more digits on top. It also is equal to 68. So it doesn't matter whether you have two groups of 34 or thirty-four groups of 2, in either case, you're going to have 68.