How to Do Basic Division With Decimals in Math

Leave plenty of room to solve the problem.

Basic division problems need to be worked out methodically to find the correct solution. However, the addition of decimals in the problem, especially when dividing by a decimal adds several steps to the problem-solving sequence. Getting the steps correct will ensure that the division problem is correctly solved, so every calculation must be done according to the methods explained in most primary math texts.

Instructions

1. Write the problem in the format shown below for dividing. Division problems may appear as fractions where 4/5 is 4 divided by 5; in this example 4 is the divisor and 5 is the dividend.

   The division problem may also be written using the traditional format shown below. The problem is worked out below. The answer is written above.

   ________ _________

   Divisor ) dividend or .005) .21

   Use the above format for this problem.

2. Move the decimal in the divisor to make the divisor a whole number. The decimal is moved to the right however many times is required to get a whole number.

   The example used here requires moving the decimal three places. After the divisor is moved for the divisor, the dividend must also be moved the same number of times. Note: Add a zero for each additional unit that must be added.

   _________ _______

   .005) .21 becomes 5 ) 210

   Since .005 requires the decimal to be moved 3 times, the .21 must also move the decimal three times. The progression of the dividend is as follows:

   1st movement - .21 > 2.1

   2nd movement -- 2.1 > 21

   3rd movement -- 21 > 210 OR 21.0 > 210

   (NOTE: the additional zero was added because one the dividend is a whole number it increases according to the decimal systems use of a 10 multiplier.)

3. Write the problem and answer out using basic division techniques.

   In this problem, 5 can go into 21 a total of 4 times. So, the 4 is placed up above the division symbol over the placeholder that marks where the division occurred (the 1). Then 20 is subtracted from the first two digits (21) of the dividend (210).

   Since the remainder is 1, the 0 from the dividend is brought down giving 10. So, 5 goes into 10 a total of 2 times. The 2 is written above the division symbol showing where the division occurred (above the 0).

   The final answer is 42 as shown above the division symbol.

   __42___

   5 ) 210

   -20

   10

   - 10

References

• Operations with Decimals

Resources

• Operations with Decimals
• Dividing by Another Decimal