New SAT Math Workbook

# Example find the sum of 84 37 and 2641 solution 84 37

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Unformatted text preview: 42 (C) 549 (D) 540 (E) 545 2. 4. 5. www.petersons.com 6 Chapter 1 5. ADDITION OR SUBTRACTION OF DECIMALS The most important thing to watch for in adding or subtracting decimals is to keep all decimal points underneath one another. The proper placement of the decimal point in the answer will be in line with all the decimal points above. Example: Find the sum of 8.4, .37, and 2.641 Solution: 8.4 .37 + 2.641 11.411 Example: From 48.3 subtract 27.56 Solution: 7 12 1 48.30 – 27.56 20.74 In subtraction, the upper decimal must have as many decimal places as the lower, so we must fill in zeros where needed. Exercise 5 1. From the sum of .65, 4.2, 17.63, and 8, subtract 12.7. (A) 9.78 (B) 17.68 (C) 17.78 (D) 17.79 (E) 18.78 Find the sum of .837, .12, 52.3, and .354. (A) 53.503 (B) 53.611 (C) 53.601 (D) 54.601 (E) 54.611 From 561.8 subtract 34.75. (A) 537.05 (B) 537.15 (C) 527.15 (D) 527.04 (E) 527.05 4. From 53.72 subtract the sum of 4.81 and 17.5. (A) 31.86 (B) 31.41 (C) 41.03 (D) 66.41 (E) 41.86 Find the difference between 100 and 52.18. (A) 37.82 (B) 47.18 (C) 47.92 (D) 47.82 (E) 37.92 5. 2. 3. www.petersons.com Operations with Whole Numbers and Decimals 7 6. MULTIPLICATION OF DECIMALS In multiplying decimals, we proceed as we do with integers, using the decimal points only as an indication of where to place a decimal point in the product. The number of decimal places in the product is equal to the sum of the number of decimal places in the numbers being multiplied. Example: Multiply .375 by .42 Solution: .375 × .42 750 + 15000 .15750 Since the first number being multiplied contains three decimal places and the second number contains two decimal places, the product will contain five decimal places. To multiply a decimal by 10, 100, 1000, etc., we need only to move the decimal point to the right the proper number of places. In multiplying by 10, move one place to the right (10 has one zero), by 100 move two places to the right (100 has two zeros), by 1000 move three places to the rig...
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## This note was uploaded on 08/15/2010 for the course MATH a4d4 taught by Professor Colon during the Spring '10 term at Embry-Riddle FL/AZ.

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