MIDTERM WEEK 2_ DECIMALS FOR SENIOR HIGH

MIDTERM WEEK 2_DECIMALS FOR SENIOR HIGH

1. 210 UNDERSTANDING DECIMALS

2. 210 “MATCHING NUMBERS”

3. Whole numbers The position of a digit within a number indicates the value of the digit. The further the digit is to the left in a number, the larger the place value .

4. Whole numbers

5. Decimal parts We now want to extend this idea to the right of the units place. Write a period to the right of the units place. This is called the decimal point. Each digit to the right of that decimal point will represent a fraction whose denominator is a power of 10. The first place to the right of the decimal point is the tenths place.

6. Decimal parts The value of the positions to the left and right of the decimal point are shown in the table below.

7. ADDITION OF DECIMALS 1. Arrange the decimals vertically with the decimal points lined up . 2. Add extra zeros if necessary so that each addend has the same number of decimal places. 3. Add the digits with the same place value from right to left, like natural numbers. 4. Insert the decimal point directly below the decimal points of the addends.

8. EXAMPLE OF ADDITION OF DECIMAL a.) 76.3 + 632.89 + 62 + 12.53

9. SUBTRACTION OF DECIMALS 1. Write the decimals vertically and line up the decimal points. 2. Add extra zeros if necessary, so that each number has the same number of decimal places. 3. Subtract the digits with the same place value from right to left, as for natural numbers. Borrow if necessary . 4. Insert the decimal point directly below the decimal points of the numbers.

10. EXAMPLE OF SUBTRACTION OF DECIMAL a.) 537.3 - 254.79

11. MULTIPLICATION OF DECIMALS 1. Ignore the decimal points and multiply the decimals as whole numbers. 2. Add the number of decimal places in the two decimals. The result is the number of decimal places in the product. 3. Insert the decimal point in the product so that it has the correct number of decimal places.

12. EXAMPLE OF MULTIPLICATION OF DECIMAL a.) 0.63 x 62.7

13. DIVISION OF DECIMALS Dividing a Whole Number by a Whole Number To divide a whole number by another whole number, where the quotient is not a natural number, divide as in division of whole numbers and then place the decimal point and the required zeros to dividend.

14. EXAMPLE OF DIVISION OF DECIMAL a.) 274.65 ÷ 34

15. CONVERSION OF DECIMALS TO FRACTION AND PERCENT

16. CONVERTING DECIMAL TO PERCENT STEPS IN CONVERTING A DECIMAL TO PERCENT 1. Multiply by 100 or move the decimal point two places to the right. 2. Add the percent sign to the number. 3. If the percent is a fraction or a mixed number, first convert the fraction into a decimal, then proceed to steps 1 and 2.

17. EXAMPLE OF CONVERTING A DECIMAL TO PERCENT a.) 0.46 b.) 0.012 c.) 7

18. CONVERTING A PERCENT TO DECIMAL STEPS IN CONVERTING A PERCENT TO DECIMAL 1. Remove the percent sign. 2. Divide by 100 or move the decimal point two places to the left. 3. If the percent is a fraction or a mixed number, first convert the fraction into a decimal, then proceed to steps 1 and 2.

19. EXAMPLE OF CONVERTING A PERCENT TO DECIMAL a.) 75.2% b.) 0.8% c.) 35%

20. CONVERTING A DECIMAL TO FRACTION STEPS IN CONVERTING A DECIMAL TO FRACTION 1. Write out the number without the decimal point. 2. Represent the number in step 1 as the numerator of the fraction. 3. The denominator is 1 followed by as many zeros as there are decimal places. 4. Reduce to simplest form.

21. EXAMPLE OF CONVERTING A DECIMAL TO FRACTION a.) 0.12 b.) 0.0375

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