This document provides instructions for adding and subtracting decimals. It emphasizes that decimals should be aligned by their place values when performing calculations by lining up the decimal points. It also recommends annexing zeros to the right of non-zero digits in decimals to maintain alignment and avoid confusion. An example calculation demonstrates these techniques and shows how to check subtraction problems by adding the residue back to the subtrahend.

1. 2-5 ADDING AND SUBTRACTING WHOLE
CHAPTER 2 NUMBERS AND DECIMALS
Adding and subtracting decimals is similar to adding and subtracting whole numbers.
REMEBER THE PLACE VALUE CHART?
DECIMAL TEN HUNDRED
THOUSANDS HUNDREDS TENS ONES TENTHS HUNDREDTHS THOUSANDTHS
THOUSANDTHS THOUSANDTHS
POINT
5 6 4 3 . 1 2 8 9 7
Look the names of the Place Value of a digit AFTER the decimal point… they are the same,
But end with THS.
When Adding and Subtracting with decimals ALWAYS align the places of the digits.

2. TO REMEMBER:
* LINE UP all the digits, depending on where the decimal point is
located. WHY?... This will align the Place Value of all the digits. You
can NOT add or subtract if the Place Value is not aligned.
Example:
3.06 + 15.430 + .025 + .2 3.06
+ 15.430
.025
__ .2___
18.715

3. TO REMEMBER:
* ANNEX ZEROS TO THE DECIMAL… this means to write zeros to the RIGHT
of the NONZERO digits in a decimal. This also will keep the Place Values
and decimal points aligned and you won’t get confused.
Example:
1.8 – 0.78 1.80
- 0.78
1.02
The Zeros will also help so that both numbers have the same number of
digits to the right of the decimal point.
Specially in subtractions is very helpful… this way you won’t just bring
down the digits of the bottom number, when there is no digit above it.

5. EXAMPLE. 235 + .378 + 0.560 + 315.62
235.000
.378
+ 0.560
315.620__

6. Do you remember the method to check if the
answer to a Subtraction is correct?
Add the answer (Residue) to the number it was subtracted (Subtrahend).
The result should be the number you started with (Minuend).
Example 1.80
- 0.78
+
1.02
1.80