VIEWS: 28 PAGES: 5 CATEGORY: SAT POSTED ON: 11/30/2010 Public Domain
Decimals • If a fraction’s denominator is a power of 10, it can be written in a special form called a decimal fraction. • Some common decimals are , , Notice that the number of decimal places corresponds to the number of zeros in the denominator of the fraction. Also note that the value of the decimal place decreases to the right of the decimal point: This decimal can be written in expanded form as follows: .1234= Sometimes a zero is placed before the decimal point to prevent misreading the decimal as a whole number. The zero has no affect on the value of the decimal. For example , .2 = 0.2. • Fractions can be converted to decimals by dividing the denominator into the numerator. Adding and Subtracting Decimals: To add or subtract decimals, merely align the decimal points and then add or subtract as you would with whole numbers 1.369 11.069 12.45 Multiplying Decimals: Multiply decimals as you would with whole numbers. The answer will have as many decimal places as the sum of the number of decimal places in the numbers being multiplied. 1.23 Dividing Decimals: Before dividing decimals, move the decimal point of the divisor all the way to the right and move the decimal point of the dividend the same number of spaces to the right (adding zeros if necessary). Then divide as you would with whole number. Example; To add 6.7 + 3.9 + 4.6 write the decimal numbers with decimal points beneath one another as follows: A) 13.2 B) 14.2 C) 15.2 D) 16.2 Solution: 6.7 Example: Rewrite 3.67 – 1.83 in columns; and then calculate. A) 1.64 B) 1.74 C) 1.84 D) 1.94 Solution: Example: The decimal .1 is how many times greater than the decimal ? A) 10 B) C) D) Solution: Converting .001 to a fraction gives . This fraction, in turn, can be written as . Cubing this expression yields . Now, dividing the larger number, .1, by the smaller number, , yields .Hence, .1 is 108 times as large as (.001)3 . The answer is (D). Practical question: 1) Calculate the following 11.832+14.9-0.3+0.7 A) 24.132 B) 25.132 C) 26.132 D) 27.132 2) Calculate the following 17.254+0.985-18.765+16.3 A) 14.839 B) 15.839 C) 16.839 D) 17.839 3) Add the following 11.321+16.543+17.765+11.9 A) 55.529 B) 56.529 C) 57.529 D) 58.529 4) Add the following 11.677+8.5+19.7+29.9 A) 66.777 B) 67.777 C) 68.777 D) 69.777 5) Multiply 17.31 * 13.5 * 11.2 A) 2610.272 B) 2617.272 C) 2447.272 D) 2557.272 NEED HELP/TUTOR? Visit www.educateNcare.com Found an error in the worksheet? Email us at info@educateNcare.com