Читать книгу Algebra I All-in-One For Dummies - Mary Jane Sterling, Mary Sterling Jane - Страница 88

Decimals are essentially fractions whose denominators are powers of 10. This property makes for much easier work when adding, subtracting, multiplying, or dividing.

 When adding or subtracting decimal numbers, just line up the decimal points and fill in zeros, if necessary.

 When multiplying decimals, just ignore the decimal points until you’re almost finished. Count the number of digits to the right of the decimal point in each multiplier, and the total number of digits is how many decimal places you should have in your answer.

 Dividing has you place the decimal point first, not last. Make your divisor a whole number by moving the decimal point to the right. Then adjust the number you’re dividing into by moving the decimal point the same number of places. Put the decimal point in your answer directly above the decimal point in the number you’re dividing into (the dividend).

Q.

A. Line up the decimal points in the first two numbers and add. Put in zeros to help you line up the digits. Then subtract the last number from the result.

Q.

A. Multiply the first two numbers together, creating an answer with four decimal places to the right of the decimal point. Then divide the result by 0.6, after moving the decimal point one place to the right in both divisor and dividend.

 

 

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