2 5 adding and sub whole num and decimals
- 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