Contributor: Katie Schnabel. Lesson ID: 14154
It is just a fact. Tasks are easier to complete when you break them down into smaller parts. Discover how multiplying 2-digit numbers can be a breeze if you do it one step at a time.
You don't know how this keeps happening. You try to keep your room clean and tidy, but it always ends up a mess! And now it has become so messy that it is overwhelming.
Tackling a big mess isn’t so bad if you break it down.
The best thing to do is start small and take it one step at a time. Maybe you start by picking up one corner of the room, or maybe put all the clothes in the hamper or all the books in the bookshelf.
Completing small tasks in the right order can make the job less scary. The same is also true of multiplying 2-digit numbers!
That’s how multiplying two-digit numbers can feel at first—it seems impossible to do in your head!
But don’t worry, just like cleaning, you can break it down into steps, and it won’t feel overwhelming at all!
Look at the problem 32 x 14.
Step One
First, set the problem up vertically — one number on top of the other. You can use a place value chart like this one.
Set up your problem so that the 32 is on top with the 3 in the tens place and the 2 in the ones place.
Then, write 14 underneath so that the 1 is in the tens column and the 4 is in the ones column.
Now you can start multiplying.
Step Two
Start with the bottom number in the ones place. In this case it is 4.
Multiply it by the top number in the ones place. In this case, it is 2.
You got it, 8! Write that down in the ones column.
Next, take the same bottom number (4) and multiply it by the top number in the tens place, In this case, it is 3.
You go it. 12.
Because there is no number in the hundreds place, you can write the whole number 12.
Step Three
Now is the trickiest and most forgettable part of multiplying 2-digit numbers: the zero placeholder!
Multiplying by the bottom number in the tens place makes your answer ten times bigger, so you must start writing in the tens place. To do that, place a zero in the ones place as a placeholder.
Step Four
Repeat the multiplication process, but start with the bottom number in the tens place. In this case, 1.
Multiply it by the top number in the ones place (2).
2, of course! But remember that the 1 in this case is actually a ten (10 x 2), so you write the 2 in the tens column.
Multiply the same bottom number (1) by the top number in the tens place (3).
Yep! 3.
Since the 1 and 3 are in the tens column, it is actually like multiplying 10 times 30. This would give you 300, so it makes sense that the 3 will go in the hundreds column.
Phew! So far so good.
Step Five
Now it is time to add it all together. Start on the right side with the ones column and work your way across.
Your final answer is 448!
You just solved a big multiplication problem by breaking it into small steps!
Now, try this one: 35 x 28. Start just like before—write the numbers one on top of the other.
Remember, begin with the bottom number in the ones place (the 8), and multiply it by the top number ones place (the 5).
That's right! 40.
Write the zero in the ones place, but then carry the 4 over to the tens place where it belongs. You will work with it in a moment when you multiply by the tens place.
Now multiply 8 by 3, which equals 24.
Simply add the 4 to your answer of 24. 24 + 4 equals 28, so write 28 below.
Great job! Now, cross off the 4 you carried so it doesn’t get in the way as you continue.
Here comes an important step! Since you're moving on to the tens place, don’t forget to put a zero as a placeholder in the ones place.
Next, multiply the bottom tens place number (2) by the top ones place number (5).
That’s right! It’s 10.
Again, you can't put the whole ten in the tens place because it is really saying 20 x 5, so place the 0 in the tens place and carry the 1 to the tens place
Now, multiply 2 times 3, which equals 6. Don't forget to add the 1 you carried over!
6 = 1 equals 7, so write 7 in the hundred place.
Awesome! Now it’s time to add everything together.
Well done! The answer is 980.
You did an amazing job multiplying those big numbers!
Now, you’re ready for the Got It? section where you can practice your skills!