Decimal Rule
How do you add decimals?
Line up numbers by place value, lining up decimal points. Add normally and drop the decimal straight down into the sum.
How do you subtract decimals?
Line up numbers by place value, lining up decimal points. Subtract normally, borrowing when necessary and drop the decimal straight down into the difference.
What do you do if, after lining up by place value, there are not enough digits in the top number to subtract a problem?
Annex zeros.
How do you multiply decimals?
You ignore the decimal point and then multiply the numbers. When finished, count the number of decimal numbers in each of the factors to find how many decimal numbers will be in the product.
How do you divide decimals?
Be sure to make the divisor whole by multiplying it by a power of 10. Multiply the dividend by the same power of 10. Place the decimal point in the quotient directly above the decimal point in the dividend. Finally, divide normally being sure to annex zeros if you arrive at a remainder.