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[Speed Math] CHECKING SUBTRACTION

Here’s an example of a SPEED MATH shortcut for CHECKING SUBTRACTION: (Check) Sub from the CHECKING ANSWERS category.

Make sure to check out SEED NUMBER CONCEPT to understand how Seed numbers are calculated. When can I use this method?

For checking any Subtraction.

This method can also be used to check problems with a combination of additions and subtractions also.

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[tubepress mode=”playlist” playlistValue=”PL9A327FD3A1C6B6BE”] Download Practice sheet for CHECKING SUBTRACTION

Notes –

1. Make sure to check out SEED NUMBER CONCEPT to understand how Seed numbers are calculated.
2. Any time you come across a seed number values greater than 1-digit, reduce it to a single digit value using the seed number concept.
3. Any time you come across a negative (-ve) seed number; add 9 to it to get is positive (+ve) value. Do the same if the seed number is = 0.
4. It is the fastest and easiest way to verify your answers.

Related Shortcuts –

Checking Division : (Check) Div

Checking Multiplication : (Check) Mul

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2 replies on “[Speed Math] CHECKING SUBTRACTION”

chitrasays:

23-18=5

in this 23 has seed no 5 * 18 has seed no 9 if we deduct 5-9 =6, and ans is 5 as seed no. so plz explain me how it came ?

LazyMaths.comsays:

For the seed number concept, 9 is treated as 0, so when you are doing 23-18, the seed numbers are 5-0=5.