About Addition of Tens, Tens and Ones
- Addition of Tens and Addition of Tens and Ones
- Addition of 10 using a Hundred Chart
- Add Tens to a Ten
- Add Tens using a Number Line
- Add Tens using Ones
- Addition of Two Digits Numbers using Tens
- Addition of Two Digits Numbers using a Number Line
- Make a 10 to Add
- Addition of Two Digit Numbers using Place Value
- Solved Examples
- Frequently Asked Questions
Addition of Tens, Addition of Tens and Ones
Addition is one of the four basic operations in mathematics. It involves adding or joining two or more groups of objects. The result of addition is called the sum and the numbers that are added are known as addends.
Here we will learn about the addition of tens or 10s to a one and a two digit number.
The concept of regrouping when adding numbers is used to explain addition of tens. Regrouping tens into ones can be explained with the following example.
Let’s take the number 30, now this can be written as 3 tens, where 3 is a single-digit number.
Addition of Ten using a Hundred Chart
A hundred chart is a 10 by 10 grid representing numbers from 1 to 100 in each square. It can be used to add 10 to any number.
We know that the addition of 10 to a number means adding 10 more to that number. In a hundred chart, adding 10 more is the same as moving down 1 row and keeping the same column in the chart. For example, if we add 10 to 24, then we move down 1 row in the same column. We reached the number 34.
Hence the required sum is, 24 + 10 = 34.
Add Tens to a Ten
We can add tens to another tens number by using regrouping. To add tens, add the tens digit and put a zero at ones place. For example if we add 30 and 40 then,
30 + 40 = 3 tens + 4 tens
Look at the tens digits, 3 + 4 = 7,
So, 3 tens + 4 tens = 7 tens. And 7 tens is 70.
Therefore, 30 + 40 = 70.
Add Tens using a Number Line
To add 10 using a number line draw a number line of tens. Then mark one of the addends and count by 10s from that number.
For example, we can add 50 and 30 using a number line as,
Start at 50 on an open number line. 30 is the same as 3 tens. So, count on by 3 tens or jump three times right. We reach the number 80 on the line.
So, 50 + 30 = 80.
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Add Tens using Ones
We can add tens to a two-digit number by expressing the two-digit number in terms of tens and ones.
Let’s take an example: Add the numbers 14 and 20.
Expand 14 as 10 + 4, which is 1 ten and 4 ones. Now 20 is 2 tens. So, we first add the tens and then add the ones.
Therefore, 1 ten + 4 + 2 tens = 3 tens + 4
Three tens and 4 is 34.
Therefore, 14 + 20 = 34.
Addition of Two Digits Numbers using Tens
To add two-digit numbers, express each number in terms of tens and ones. Then add the corresponding digits in tens and ones place to get the final sum.
For example, if you want to add 22 and 24 then,
22 can be written as 2 tens and 2 ‘ones’.
24 can be written as 2 tens and 4 ‘ones’.
We first add the ‘ones’ here
2 + 4 = 6, that is 6 ‘ones’.
Then we add the 10s,
2 ‘tens’ + 2 ‘tens’ = 4 ‘tens’ so now we have 4 ‘tens’ and 6 ‘ones’ which is 40 + 6 = 46.
Therefore, 22 + 24 = 46
Addition of Two Digits Numbers using a Number Line
We can add two-digit numbers using addition on a number line by expressing any one addend in terms of ‘tens’ and ‘ones’. Then we draw a number line and mark the other addend on the line. Starting from this addend, count by ‘tens’ and then by ‘ones’, as per the other addend, to get the sum. Another way can be to count by ‘ones’ first and then by ‘tens’.
For example, we can add 36 and 32 using a number line as,
32 can be written as 3 tens and 2 ones. Draw a number line. Mark 36 on the line. So from 36 we take 3 jumps of ten and 2 jumps of one.
So we count three tens and 2 ones to reach 68 on the line.
Another way: Let’s count by ones and then tens.
So we jump 2 times by one and then 3 times by ten to reach 68 again. The answer remains the same both ways.
Therefore, 36 + 32 = 68.
Make a 10 to Add
We know that 1 ten is 10 ones. Hence, if in an addition equation any addend has more than 10 or more ones then we can express it in terms of tens and then add as usual.
For example, If you want to find 28 + 4 then,
28 + 4
= 2 tens + 8 + 4 (28 can be written as 2 tens and 8 ones which is 8)
= 2 tens + 8 + 2 + 2 (4 can be written as 2 + 2)
= 2 tens + 1 ten + 2 (simplify)
= 3 tens + 2 (simplify)
= 32 (add)
So 28 + 4 = 32.
Addition of Two Digit Numbers using Place Value
We can use the concept of place value to add two-digit numbers. For this identify the digits at the tens and ones place in the two addends. Then add the corresponding digits of tens and ones place. If the sum of ones place digits is equal to or greater than 10, then regroup it in tens. Then add as usual.
For example, You can add 36 and 37 as,
36 + 37
= 3 tens + 6 ones + 3 tens + 7 ones (36 can be written as 3 tens and 6 ones and 37 can be written as 3 tens and 7 ones)
= 3 tens + 3 tens + 6 + 7 (6 ones and 7 ones can be written as 6 and 7)
= 6 tens + 6 + 4 + 3 (add and write 7 as 3 + 4)
= 6 tens + 1 ten + 3 (6 + 4 = 10 which can be written as 1 ten)
= 7 tens + 3 (add)
= 73 (add)
Solved Examples on Addition of Tens and Ones
Example 1: Find 40 + 50 = ?
Solution:
To add tens, add the tens digit and put a zero at ones place. To add 40 and 50 we can follow steps as,
Look at the tens digit,
4 + 5 = 9
So, 4 tens + 5 tens = 9 tens. And 9 tens is 90.
Therefore, 40 + 50 = 90
Example 2: Find 50 + 40 on the number line.
Solution:
To add 50 and 40, first draw a number line and mark 50. Count on 4 tens. The number obtained is 90.
Therefore, 40 + 50 = 90.
Example 3: Add: 43 + 16
Solution:
43 + 16
4 tens + 3 ones + 1 ten + 6 ones (write 43 as 4 tens and 3 ones and 16 as 1 ten and 6 ones)
= 4 tens + 1 ten + 3 + 6 (3 ones and 6 ones can be written as 3 and 6)
= 5 tens + 9 (add)
= 59 (add)
Therefore, 43 + 16 = 59.
Example 4: Smith played football for 38 minutes. Then he played cricket. He played for 54 minutes in total. How long has he played cricket?
Solution:
Smith played for 54 minutes in total. If he played football for first 38 minutes, then
What we need to find,
38 + ? = 54
To find the unknown addend, draw a number line. Start at 38. Count on by tens and ones until we reach 54.
Find the sum of tens and ones jumped,
10 + 1 + 1 + 1 + 1 + 1 + 1 = 16
Therefore, Smith played cricket for 16 minutes.
The sum of 10 tens is 100, that is 1 hundred.