tailieunhanh - Success step english 4

Tham khảo tài liệu 'success step english 4', ngoại ngữ, anh ngữ phổ thông phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | CBEST MINI-COURSE 13 - 67 1. Notice the common denominator of the fractions 7 2. Add that number to the numerator of the top fraction 5 7 12 3. Subtract one from the top integer 13 - 1 12 4. Subtract as usual 12y- 6 -67 67 HOT TIP When adding or subtracting fractions you can use the laser beam method. 1. First change to improper fractions then multiply crosswise . 1 6 7 6 7 2. Next multiply the denominators 6 X 7 42 3. Add or subtract the top numbers as appropriate and place them over the multiplied denominator to get your answer 7 18 25 25 42 Multiplying and Dividing Fractions When multiplying fractions simply multiply the numerators and then multiply the denominators 5 XI 1 When dividing turn the second fraction upside- down then multiply across -2 -2 is the same as -2 X - 3 When working with problems that involve mixed numbers such as 6y X 5-3- change the numbers to improper fractions before multiplying. With 6-y multiply the denominator 2 by the whole number 6 to get 12 then add the numerator 1 for a total of 13. Place 13 over the original denominator 2. The result is 13 2 . HOT TIP When you re working with two fractions where the numerator of one fraction can be divided by the same number as the denominator of the other fraction you can reduce even before you multiply ói X 51 X -Ịó- 62 X 5 3 2 X 3 Divide both the 2 and the 16 by 2 113 x 8 104 34 When multiplying or dividing a fraction and an integer place the integer over 1 and proceed as if it were a fraction. 13 X ị 11X 4 11 61 13 X 2 1 X 2 2 62 Choosing an Answer When you come up with an answer where the numerator is more than the denominator the answer may be given in that form as an improper fraction. But if the answers are mixed numbers divide the denominator into the numerator. Any remainder is placed over the original denominator. In the case of -268- 208 divided by 6 is 34 with a remainder of 4 yielding 34- . This answer probably will not be there so reduce 4 to -2-. If -26 is not an answer choice .