Adding a 1Digit Number to a 2Digit Number
Basics on the topic Adding a 1Digit Number to a 2Digit Number
Adding 1 Digit Numbers to 2 Digit Numbers
This text will teach you about twodigit numbers and how to do written addition by adding onedigit numbers to twodigit numbers. But first, let’s go over the meaning of one digit numbers and two digit numbers and how to represent them.
Revision – Digits
What is a 1 digit number? Digits in maths are the position of numbers. A one digit number is a single number symbol used to represent zero to nine. These numbers (0, 1, 2, 3, 4, 5, 6, 7, 8, and 9) are called one digit numbers because they only have one digit, or number symbol, used to represent them.
When we put two of these number symbols (0, 1, 2, 3, 4, 5, 6, 7, 8, and 9) next to each other, it is called a two digit number. For example, numbers like 12, 34, 56, 78, or 90 are two digit numbers. So when you have a number larger than ten, you have a twodigit number. As you know, numbers can be displayed using a place value chart. Here, the digits are represented by the terms ones and tens. The number 12 for example looks like this when put in a place value chart:
Tens  Ones 

1  2 
For the number 12, there is a 1 in the tens place and a 2 in the ones place.
Adding 1 Digit Numbers to 2 Digit Numbers – Example
Let’s learn more about adding numbers with different digits together and an easy strategy to use for solving these equations! Sometimes we have to add a two digit number and one digit number together. When this happens, always start with the two digit number. Then, add the one digit number to it. The answer to the problem is called the sum.
There are many ways to add a one digit number to a two digit number, but here we will use a tens frame! Let's use the equation eleven plus three as an example.
First, circle the one digit number, three. Then, fill in the tens frame with three counters.
Next, start counting on from the two digit number, eleven, and stop when you reach the last counter which would be fourteen.
Fourteen is the answer so we write that in the sum position at the end of the equation.
Adding 1 Digit Numbers to 2 Digit Numbers – Summary
How do you add two digit numbers to one digit numbers? Remember, when adding a one digit number to a two digit number using a ten frame, you should follow these steps:
Step #  What to do 

1  Start by circling the one digit number. 
2  Then, fill in the tens frame with that number of counters. 
3  Next, start countingon from the two digit number. 
4  Stop when you reach the last counter. This number is the answer! 
 Start by circling the one digit number.
 Then, fill in the tens frame with that number of counters.
 Next, start counting on from the two digit number.
 Stop when you reach the last counter. This number is the answer!
Have you practised yet? On this website, you can also find interactive exercises for adding 1 digit numbers to 2 digit numbers along with worksheets and further activities.
Transcript Adding a 1Digit Number to a 2Digit Number
Mr. Squeaks and Imani are at the comic shop adding to their collections. They are huge fans of The Adventures of RoboRodent, a crime fighting critter who’s part machine, part animal. Mr. Squeaks has thirtyfive comics and wants to see how many he will have if he buys five more. Imani has fortynine and wants to know their total if they add another six. Let's help them find out how many comics they will have by "Adding a One Digit Number to a Two Digit Number!” A digit is a single number symbol we use to represent zero to nine. These numbers are called one digit numbers because they only have one digit, or number symbol, used to represent them. When we put two of these number symbols next to each other, it is called a two digit number. Sometimes we have to add a two digit number and one digit number together. When this happens, always start with the two digit number. Then, add the one digit number to it. The answer to the problem is called the sum. There are many ways to add a one digit number to a two digit number, but today we will use a tens frame! First, circle the one digit number, three. Then, fill in the tens frame with three counters. Next, start countingon from the two digit number, eleven and stop when you reach the last counter. Let's count together eleven, twelve, thirteen, fourteen! Fourteen is the answer! Write it here. Now, let's help Mr. Squeaks work out how many comics he will have if he adds five more to his collection of thirtyfive. First, circle the one digit number, five. Then, fill in the tens frame with five counters. Next, start counting on from the two digit number, thirtyfive. Let's count together, thirtyfive, thirtysix, thirtyseven, thirtyeight, thirtynine, forty! We stopped on forty, so we write it here as the sum. Mr. Squeaks will have forty comics! We can help Imani now! Remember, Imani has fortynine comics and wants to add another six. What is our first step? First, circle the six. Then, fill in the tens frame with six counters. What happens next? Next, we start counting on from fortynine. What number do we end on? We end on fiftyfive, so we write it here as the answer. Imani will have fiftyfive comics! Before Mr. Squeaks and Imani leave the shop, let's remember! Today we learnt about adding a one digit number to a two digit number using a tens frame. Start by circling the one digit number. Then, fill in the tens frame with that number of counters. Next, start counting on from the two digit number. Stop when you reach the last counter. This number is the answer! Look who's coming in just as Imani and Mr. Squeaks are about to leave. Is it a bird? Is it a plane? No! It's Robo Rodent! "Can we get your PAWtograph?!"
Adding a 1Digit Number to a 2Digit Number exercise

What is 15 + 7?
HintsRemember, the sum is the total of both numbers together.
Remember, you need to highlight the two places that show the sum, or total.
SolutionThey have 22 comics altogether.
We can find the sum once we count on using the tens frame. The sum is the last number and we write it under the equation.

How many comics does Mr Squeaks have now?
HintsRemember, start at the two digit number, and count on using the tens frame.
The number you reach is your sum or answer.
SolutionMr. Squeaks now has 47 comics.
We started at 40, then added 7 more using the tens frame.
40 + 7 = 47
The sum of the comics is 47.

How many comics will Imani have?
HintsRemember, use the tens frame to count up starting at the two digit number.
Remember, the sum is the number you finish counting on.
SolutionImani will have 58 comics!
If we start at 49, then count up 9, the sum is 58.

Fill in the steps to solve the problem.
HintsIdentify the one digit number first and add that many counters to the tens frame.
In this example, it is 3.
Count on from the two digit number to find the sum.
In this example we count on three from 11 to reach 14.
SolutionWhen adding a one digit number to a two digit number:
 First, we identify the one digit number by circling it. In this case 8.
 Next, we fill in the tens frame, this time with 8 counters.
 Then, we count on from the two digit number, this time 55.
 Finally, we find the sum  the number we land on. This time it is 63.

Complete and solve the problem.
HintsRemember, start at the two digit number, and count on.
When we are counting on from 13, what comes next? Use this number line to help you.
The final number you land on is your sum or answer.
SolutionImani now has 19 comic books in total.
We count on 6 from 13.
Using the tens frame, we count until 19.
19 is our answer.

What is the sum?
HintsYou can draw your own tens frames to help you to find the answers.
Count up from the two digit number.
SolutionIf we count on from each two digit number by each one digit number, we get the following answers:
35
 28 + 7
 29 + 6
 32 + 3
 27 + 9
 28 + 8
 30 + 6
 32 + 7
 34 + 5