Multiplying Tens
Basics on the topic Multiplying Tens
Multiplying by Multiples of 10
What are the multiples of 10? A multiple of ten is a number that ends in a zero. Some examples are 10, 20, 30, 40, 50, and so on. Multiplying by multiples of ten means that you multiply a number by 10, 20, 30, 40, 50, and so on.
Multiplying by Multiples of 10 – Example
How do you explain multiplying by 10? Well, let’s take a look at this example from the above math video teaching multiplying by 10s, two times twenty.
When multiplying by 10s, we write a zero in the ones place as a placeholder, since any number multiplied by zero will always be zero.
Next, we move to the next place value, the tens place, and we multiply the two by the two above.
Two times two is four, so we write this in the tens place next to the zero. Now we have finished solving! Two times twenty gives a product of forty, which is the solution to the problem.
Multiplying by Multiples of 10 – Summary of Steps
To multiply by tens, follow these steps:
Step #  What to do 

1  Set up the problem, using standard algorithm. 
2  Write a zero in the ones place as a placeholder. 
3  Multiply the tens place digit by the single digit and write the product next to the zero. 
This text can serve you as an anchor chart containing information about multiplication by tens. After watching the video, you will find interactive multiplying by 10s exercises, worksheets (also downloadable as PDF) and more activities for further practice.
Transcript Multiplying Tens
Mr. Squeaks has built a handheld clone machine, which works by multiplying single digit objects by multiples of tens! Mr. Squeaks wants to calculate the final product first so that he doesn't clone too many objects. Mr. Squeaks needs help multiplying tens. A multiple of ten is a number with a zero in the ones place. Ten, twenty, thirty, and so on are all multiples of ten. To multiply a single digit number by a multiple of ten, first, set up the problem, aligning the place values. Next, write a zero in the ones place. A zero is added here because any number multiplied by a multiple of ten will always have a zero in the ones place! Finally, multiply the tens place digit by the single digit. Four times five gives a product of twenty, which means four times fifty is two hundred! Mr. Squeaks only has two metal rods left and wants to clone them twenty times. Set up the problem, writing two times twenty like this. Next, write a zero in the ones place. Now look at the two in the tens place and multiply it by two. Two times two is four, so write it in the tens place. The product of two times twenty is forty! Mr. Squeaks is happy with forty metal rods, so he uses his machine! "This sure is hungry work, but I only have three slices of cheese left!" Let's help multiply his cheese slices by forty, so he has plenty to eat. Write three times forty, aligning the place values. What is the next step? Next, write a zero in the ones place. What should we do next? Look at the four in the tens place and multiply it by three. What is three times four? Three times four is twelve. We write twelve in the hundreds and tens place. Three times forty gives our solution one hundred twenty. One hundred twenty slices of cheese should last Mr. Squeaks a while. Before we join Mr. Squeaks for snack time, let's review! Remember, when multiplying by multiples of ten, first, set up the problem, aligning the place values. Next, write a zero in the ones place. Finally, multiply the tens place digit by the single digit to get the product! "This cheese looks delicious!" Wait, that's not a chair, Mr. Squeaks! "Woah, I definitely don't need that many Imani's!"
Multiplying Tens exercise

Multiples of ten.
HintsMultiples of ten all have the same digit in the ones place. Can you remember which digit?
These numbers are multiples of ten.
All multiples of ten have a 0 in the ones place.
Solution10, 30, 60 and 70 are all multiples of ten.
They all have a 0 in the ones place.

How do we multiply tens?
HintsThis is our first step.
This is what we would do next.
Finally, we would have this.
Solution First, set up the problem, aligning the place values.
 Write 0 in the answer's ones place.
 Multiply the tens place digit by the single digit.
 Finally, write your answer.

How many of each item will there be?
HintsYou can write out your multiplication problems like this to help you solve them.
Write a 0 in the product's ones place, as we know the product will end in 0.
Multiply the single digit by the digit in the tens place.
SolutionMr. Squeaks would end up with this many items after cloning!
Seeds
 3 x 30 = 90
 2 x 40 = 80
 5 x 60 = 300
 4 x 70 = 280

What will the products of these clones be?
HintsPlace one number on top of the other to help you solve the equation.
Place a 0 in the product's ones place and then multiply the single digit by the digit in the tens place.
Solution120
 2 x 60
 3 x 40
 4 x 30
 3 x 80
 2 x 120
 4 x 60
 6 x 40
 8 x 30
 6 x 50
 5 x 60

Which box should the planks of wood go in?
HintsHow many planks did Mr. Squeaks start with? What is he multiplying that number by?
Mr. Squeaks is trying to solve 7 x 10 =.
If we are solving 7 x 10, what are the steps we need to take?
SolutionMr. Squeaks would put the cloned planks of wood in the box with the label, 70.
He started with 7 planks and multiplied them by 10. If we multiply 7 x 10 we get 70.

Mr. Squeaks' party.
HintsFind the key information in each passage.
 How many items does Mr. Squeaks start with?
 What is he multiplying that number by?
Follow the steps for multiplying a single digit number by a multiple of ten to find the answer.
SolutionMr. Squeaks is so happy, he had a great party!
 Mr. Squeaks wants to put some balloons up around the room. He has 3 balloons. He decides to use his cloning machine and multiply them by 70. He now has 210 balloons.
 Mr. Squeaks finds 6 party hats. He decides to clone them and inputs 30 into his cloning machine. He now has 180 hats. That should be plenty!
 It wouldn't be a party for Mr. Squeaks without cheese! He finds 3 pieces of cheese in his fridge but decides to use the machine to multiply them by 90. There are now 270 pieces of cheese, yum!
 Mr. Squeaks decides he also wants to decorate with some banners. He finds 4 packs of banners and multiplies them by 40. He now has 160 packs of banners.
 Mr. Squeaks made so many decorations (and pieces of cheese!) but only 2 guests turned up! "Never mind," he thought as he pulled out his cloning machine and inputted 100 into it. Now there are 200 guests! Let's party!