 Mental Subtraction Strategies | Orchids International School Mental Maths

Mental Subtraction Strategies

What is subtraction?

• To find the difference between any numbers.

We will learn some easy methods to do subtraction mentally. Subtract 1-digit number from 1-digit number

• Subtraction by counting forward

• Consider the second number (Subtrahend) and count the number of steps forward till getting first number (Minuend).

Example: Method: • In the above example, we start counting from number 5 till getting the number 8.
• Then count the number of steps that we have counted forward.
So, we get: • Subtraction by counting backwards

• Consider the first number (Minuend) and count the number of steps backwards equal to the second number (Subtrahend).

Example: Method: • In the above example, we start counting backwards from the number 7.
• We have subtrahend as 3, so we count 3 steps backwards.
• We reached at number 4. It is our answer.
• This method will make our subtraction easier.
So, we get: Subtract 1-digit number from 2-digit number

• Subtract any 1-digit number from 10 using number bonds of 10.

• We use here number bonds of 10.

Example: Method: • In the above example; we know that, if we add 3 to 7, we get 10. (Number bond of 10: 7 + 3 = 10)
• So, here 7 is 3 less than 10.
So, we get: Example 2: Method:

• In the above example; we know that, if we add 8 to 2, we get 10. (Number bond of 10: 2 + 8 = 10)
• So, here 2 is 8 less than 10.
So, we get: • Subtraction by splitting of 2-digit number into tens and ones

• Split 2-digit number into Tens and Ones, make subtraction of Ones.

Example: Method: • In the above example, we split 28 into 20 Tens and 8 Ones.
• Then subtract 5 from 8 Ones. We get 3.
• Adding 20 Tens and 3 Ones, we get 23.

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