In Mathematics, addition can be defined as combining two or more than two numbers. Adding two numbers of 3 digits is done by adding ones with ones, tens with tens and hundreds with hundreds.
The symbol for addition is +
For example: 4 + 2 = 8
Addition of numbers
Addition of one-digit numbers
Ravi has eight cows. He purchased two more cows. Now, how many cows does he have?
Sol:
8 cows + 2 cows = 10 cows
OR
| Â Â 8 |
| + 2 |
| Â Â 10 |
Ravi has 10 cows.
In addition, when a ‘0’ is added to a number, we get the same number.
For example: 2 + 0 = 2
OR
| Â Â 2 |
| + 0 |
| Â Â 2 |
Addition of two numbers without carryover
For addition of two numbers of two digits:
- Write ones below the one’s of the first number and tens below the ten’s of the first numbers.
- Now add one’s of both numbers and ten’s of both numbers.
For example:
There are 42 roses and 20 tulips in a garden. How many flowers are there in the garden?
Sol:
42 + 20 = 62
OR
| T | O | |
| 4 | 2 | Roses |
| 2 | 0 | Tulips |
| 6 | 2 | Flowers |
There are 62 flowers in the garden.
Addition of two numbers of three-digits with and without carryover
For adding two numbers of three digits:
Write one digit under one’s digit, ten’s digit under tens digit, and hundred’s digit under the hundreds digit of the first number.
For example:
- Addition of two numbers without carryover
There are 423 cows, and 312 buffaloes grazing in a field. How many animals are grazing in the field?
Sol:
423 + 312 = 735
OR
| H | T | O |
| 4 | 2 | 3 |
| 3 | 1 | 2 |
| 7 | 3 | 5 |
There are 735 animals grazing in the field.
- Addition of two numbers with carryover
There are 365 cows in Ramu’s village and 182 cows in Raju’s village. How many cows are there in total in the two villages?
Sol:
365 + 182 = 547
OR
| H | T | O |
| 3 | 6 | 5 |
| 1 | 8 | 2 |
| 5 | 4 | 7 |
There are 547 cows in the two villages.
In the above example, one is carried over from the ten’s place to the hundred’s.
Subtraction of numbers
In mathematics, subtraction can be defined as reducing or removing a given number to a smaller number or reducing it to zero.
While subtracting, we always subtract the digit below from the above number.
We subtract ones from ones, tens from tens and hundreds from hundreds of the two numbers in subtraction. The symbol of subtraction is –.
For example: 4 – 2 = 2
Subtraction of one-digit numbers
Eight parrots were sitting on a mango tree. Four out of eight flew away. How many parrots were left on the mango tree?
Sol:
| Eight parrots | Â – | Â Four parrots | Â = | Four parrots |
OR
| Â Â 8 |
| –Â 4 |
| Â Â 4 |
There were four parrots left on the mango tree.
Subtraction of a one-digit and a two-digit number from another two-digit number
When we subtract a one-digit number from a two-digit number, we subtract the ones digit from the ones digit and write the tens digit down.
For example:
42 – 2 = 40
| T | O |
| 4 | 2 |
| – | 2 |
| 4 | 0 |
Similarly, subtracting a two-digit number from another two-digit number.
45 – 15 = 30
| T | O |
| 4 | 5 |
| 1 | 5 |
| 3 | 0 |
Subtraction of three-digit numbers with borrowing
We borrow one ten’s from the two ten’s while subtracting the greater number with smaller ones.
For example:
Subtract 17 from 36.
36 – 17
| T | O |
| 3 | 6 |
| 1 | 7 |
| 1 | 9 |
In the above example, we had to borrow one from the tens. So now 6 become 16 and 16 – 7 = 9. The 3 in the tenth place become 2 and 2 – 1 = 1. Therefore, by subtracting 17 from 36, we get 19.
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