Subtraction of big no.
Subtraction1 - Subtraction without carrying
To calculate a complicated subtraction, you start as you do with when adding : you write down the two numbers one below the other, ligning up the numbers of unities, but also writing the biggest number before. We calculate 476-145.
Start with the units column. Count how many you need to get from the number below to the number on the top. Here, from 5 to 6 you need 1 so you have to write 1 below the line.
Then you do the same for the tens column : from 4 to 7 you need 3 so you write a 3 below the line.
Finally for the hundreds column, from 1 to 4 you need 3 so you write the number 3 below the line. You can read the final result of the subtraction: 476-145=331.
To train yourself
Use this method to answer the following question :
What is the value of 535 - 302 ?
2 - Subtracting and carrying
Sometimes, in a column, the number on top is smaller than the one below. For example, for 752-318 you should start, for the units column, with calculating "from 8 to get to 2". It is not possible.
When you are in this situation, you add 1 before the number on top, and 1 on the right of the number below in the column on the left.
Next, you count "from 8 to get to 12". The result is 4 so you write 4 below the line.
For the tens column you cannot count "from 1 to 5" as you have to add to 1 the number you have just carried over. So you count "from 2 to 5". The result is 3, so you place a 3 below the line.
Finally, for the hundreds column, you count "from 3 to get to 7". The result is 4 so you place the number 4 below the line and you can read the final result of the subtraction : 752-318=434.
Go on training yourself!
Use this method to answer the following question :
What is the value of 736 - 527 ?
To calculate a complicated subtraction, you start as you do with when adding : you write down the two numbers one below the other, ligning up the numbers of unities, but also writing the biggest number before. We calculate 476-145.
Start with the units column. Count how many you need to get from the number below to the number on the top. Here, from 5 to 6 you need 1 so you have to write 1 below the line.
Then you do the same for the tens column : from 4 to 7 you need 3 so you write a 3 below the line.
Finally for the hundreds column, from 1 to 4 you need 3 so you write the number 3 below the line. You can read the final result of the subtraction: 476-145=331.
To train yourself
Use this method to answer the following question :
What is the value of 535 - 302 ?
2 - Subtracting and carrying
Sometimes, in a column, the number on top is smaller than the one below. For example, for 752-318 you should start, for the units column, with calculating "from 8 to get to 2". It is not possible.
When you are in this situation, you add 1 before the number on top, and 1 on the right of the number below in the column on the left.
Next, you count "from 8 to get to 12". The result is 4 so you write 4 below the line.
For the tens column you cannot count "from 1 to 5" as you have to add to 1 the number you have just carried over. So you count "from 2 to 5". The result is 3, so you place a 3 below the line.
Finally, for the hundreds column, you count "from 3 to get to 7". The result is 4 so you place the number 4 below the line and you can read the final result of the subtraction : 752-318=434.
Go on training yourself!
Use this method to answer the following question :
What is the value of 736 - 527 ?
