Addition and Subtraction with Decimal Numbers:
Finding the sum of decimal numbers can be accomplished by writing the decimal numbers one under the other and keeping the decimal points in a line vertically. Using this method, the whole numbers will be added to whole numbers, tenths added to tenths, hundredths to hundredths, and so on. The decimal point in the sum (the answer) is in the same line with the decimal points in the numbers that were added.
For example, to add 2.357 + 6.14, we write:
Finding the difference of decimal numbers works exactly the same way as finding the sum of decimal numbers by writing the decimal numbers one under the other and keeping the decimal points in a line vertically.
Time to Practice Adding and Subtracting Decimals
1) 70.8 + 0.491 = ?
2) 251 + 18.14 = ?
3) 95.0 – 5.86 = ?
4) 25.2 – 1.85 = ?
Write down your answers in order and you’ll check them later.
Multiplication with Decimal Numbers
The product of decimal numbers is found the same way whole numbers are multiplied. But you have to correctly place the decimal point in the product. Look at the example below that illustrates how the decimal point is to be placed in the product.
Division with Decimal Numbers
The process of division with decimal numbers is, in effect, the same as division with whole numbers with the added concern of where to place the decimal point in the quotient.
To divide decimal numbers first move the decimal point in the divisor to the right so that the divisor is a whole number.
Next, move the decimal point in the dividend the same number of places to the right.
Then place the decimal point in the quotient directly above the new decimal point in the dividend.
Finally divide just as with whole numbers.
Time to Practice Multiplying and Dividing Decimals
5) 34.370 divided by 0.70?
6) 0.491 x 70.8 = ?
7) 1.06 x 2.22 = ?
8) 2.332 divided by 2.2 ?
Write out the questions and your work and your answers.