Decimal division is the process of dividing numbers that contain decimal points. The key is to convert the problem into whole number division. Let's see how we divide 6.4 by 0.8. First, we remove the decimal from the divisor by multiplying 0.8 by 10 to get 8. Then we multiply the dividend 6.4 by the same amount to get 64. Finally, we divide 64 by 8 to get our answer of 8.
The secret to decimal division is understanding how to move decimal points. When we have 12.6 divided by 0.3, we need to eliminate the decimal from the divisor. We move the decimal point in 0.3 one place to the right to get 3. We must do the same to the dividend, moving the decimal in 12.6 one place right to get 126. Now we can divide 126 by 3 to get 42.
Now let's try long division with decimals. We have 8.4 divided by 2.1. First, we convert both numbers to whole numbers by moving the decimal point one place to the right, giving us 84 divided by 21. We set up the long division and ask: how many times does 21 go into 84? We calculate 21 times 4 equals 84, so it goes exactly 4 times. Therefore, 8.4 divided by 2.1 equals 4.
Sometimes our answer will have decimals too. Let's divide 7.5 by 3. We set up long division with 3 dividing into 7.5. First, 3 goes into 7 twice, since 2 times 3 equals 6. We subtract to get 1, then bring down the 5 to make 15. Now 3 goes into 15 exactly 5 times. We place the decimal point in our answer directly above the decimal point in the dividend. So 7.5 divided by 3 equals 2.5.