How do you multiply a 2 digit by a 2 digit

Well, what I do is first write the problem vertically. I'm going to make an example of 21 times 16. You see the 1 in the 21 and the 6 in 16? Multiply that and place it below your expression. Then you multiply 20 x 6 because you must add a 0 into the number since it is in the tens place and do the same and place it below. Then do it the other way across, 10 x 1 equals 10, place it below. Lastly, multiply the 2 tens place digits, 20 times 10, and place it below. Add up all your numbers below, and you will get your final product. Sorry if this confuses you.

Steps Write down the problem ... Multiply the number in the ones place of the bottom number by both digits of the top number ... Write a "0" in the units column below the first product ... Multiply the number in the tens place of the bottom number by both digits of the top number ... Add up the two products.