Addition and Subtraction | Primary Math eBook

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Addition and Subtraction | Primary Math eBook

Addition and Subtraction

Addition

Addition means to add together different values:

6

=

2

+

4

I now have six apples.

 

I receive two more apples.

 

I have four apples.

   4     ADDENDUM

+ 2    ADDENDUM

   6    SUM

Step 1: ALWAYS put your numbers into column form, making sure that the ones are properly aligned on the right-most side. If necessary, draw a place value table like the one below:

Hundred Thousands

Ten Thousands

Thousands

Hundreds

Tens

Ones

     

5

7

8

   

+

3

6

9

Step 2:

Add together the individual numbers, starting with the ONES, and moving to the left side.

    578                       8 + 9 = 17, therefore write down 7 and put the 1 in the Tens column

+ 369

 

                                  7 + 6 = 13, but add the 1 from before and write down the 4 from 14 in the                                       Tens column, and put the 1 in the Hundreds column

                                 Finally, add the 5 and 3, and the 1 from before and write down 9 in the                                             Hundreds column

Therefore, your final answer should look like this:

    1 1

    578

+ 369

   947

Subtraction

Subtraction means to take away a value from another value.

6

=

2

-

8

I now have six apples.

 

I give two apples away.

 

I have eight apples.

  8       MINUEND

- 2      SUBTRAHEND

6        DIFFERENCE

Step 1: ALWAYS put your numbers into column form, making sure that the ones are properly aligned on the right-most side. If necessary, draw a place value table like the one below:

Hundred Thousands

Ten Thousands

Thousands

Hundreds

Tens

Ones

     

5

3

2

   

-

1

6

9

Step 2: Subtract the individual numbers, starting with the ONES, and moving to the left side.

 

   532     

- 169

 

     2 – 9 is not possible, so we “borrow” a 1 from the 3 in the Tens place (turning the 3 into a 2       as we do so), and treat the 2 as it were a 12. Therefore, 12 – 9 = 3. We write down the 3 in           the Ones column.

     Now, we look not at 3 – 6 in the Tens column, but at 2 – 6, because we “borrowed” 1 for the       above step. Likewise, we “borrow” a 1 from the Hundreds column (thus, the 5 now becomes       a 4), and ask ourselves 12 – 6 = 6, of course.

     Finally, we take our 5 – which is actually a 4 now – and subtract 4 – 1 = 3.

     Therefore, your final answer should look like this:

  4 12 12

   532

- 169

   363