One by Two Digit Multiplication is a First Step to Multiplying Bigger Numbers
The easiest multi-digit multiplication problem is simply multiplying a two digit number by second single digit number. This winds up being a smaller part of the process used to multiply multiple digit numbers generally, so seeing how this works in a simple example is an extremely useful stepping stone on your multiplication journey.
It’s All Multiplication Facts, Just One Digit at a Time
To multiply a two digit number by a one digit number, you’re going to basically break the number down into two single digit multiplication facts.
When multiplying two numbers together, the answer is called the product and the numbers multiplied together are called multiplicands. For discussion’s sake, we’ll talk about the two digit number as the “two digit multiplicand” and the single digit number as the “single digit multiplicand.”
Take the digit in the ones place in the two digit multiplicand (the digit on the right). Multiply that digit by single digit multiplicand. These are all single digit multiplication facts and you should have those memorized.
The result will be either a single digit product, or a two digit product (the largest number you could get is for 9×9=81.) If you got a single digit fact, just write it down as the first digit (the ones digit) for the final product.
If the answer to that math fact is a two digit value, write the ones place value down and carry the tens digit by writing it over the top of the tens digit in the two digit multiplicand. We’ll use that carried value shortly.
Now, take the tens digit from the original two digit multiplicand and multiply it by the single digit multiplicand, just like we did for the ones digit. Again, that will give you a one or two digit result. However, before we use this number, we need to add in the carried amount from the ones digit (if we got one).
The result of that second math fact (and with the carry) represent the number of tens in our final result. You’ll write that right next to the ones digit in the final product we wrote earlier.
Here’s an visual example of these steps…
This process of taking a single digit and multiplying it across all of the digits in the larger multiplicand is something that repeats when you multiply larger numbers, so understanding this super simplified problem is good preparation for larger multiplication tasks… Keep reading for more multiplication tips!
