SUBTRACTION

SUBTRACTION

Subtraction is one of the most basic operations in mathematics and is directly linked to the idea of ​​taking or knowing how much is missing.

Example:

Joãozinho had 4 strollers before giving 1 to his cousin. It is not difficult to see that Joãozinho was left with 3 carts.

 

The symbol used to represent the subtraction is the (-) . Look:

4 – 1 = 3

In this example we have to:

4 is the MINUENDO

1 is SUBTRAENDO

3 is the DIFFERENCE or REST

 

 

THE ALGORITHM

The structure of the subtraction algorithm is as follows:

To use the algorithm, the minuendo and subtrendendo must be positioned from right to left, so that first we subtract the units, then the tens, hundreds, etc.

 

Comments

  • The order of the parcels makes all the difference. The minuendo must always be placed above the subtrend;
  • The algorithm can be used to subtract just one minuend from a subtrend;
  • The minuendo must be greater than the subtracting.

 

 

Example 1. Subtract 65 from 42.

Units: 5 – 2 = 3

Dozens: 6 – 4 = 2

 

 

Example 2. Subtract 968 from 151.

Units: 8 – 1 = 7

Dozens: 6 – 5 = 1

Hundreds: 9 – 1 = 8

 

 

Example 3. Subtract 846 from 572.

We now have a special case. When we try to subtract the tens, we have to 4> 7. Whenever this occurs, the 4 will “borrow” with the number to its left, changing to 14. The 8 in turn, will become 7.

Units: 6 – 2 = 4

Dozens: 14 – 7 = 7

Hundreds: 7 – 5 = 2

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