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GMAT Math: Fractions Decimals Ratios Interest

Subjects : gmat, math
Instructions:
  • Answer 24 questions in 15 minutes.
  • If you are not ready to take this test, you can study here.
  • Match each statement with the correct term.
  • Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. To reduce a fraction - find a factor of numerator that is also a factor of the denominator. It saves time to find the bigger factor when you find a common factor - cancel it. Example - 12/15 = 4x3/5x3 = 4/5 - Reducing a larger fraction before work to






2. It is easier if it converted to all fraction. You multiply the denominator by integer then add the numerator and place the resulting number over the original denominator - Example - 3 1/2 = 3 = 6/2 = 1/2 + 6/2 = 7/2






3. More complicated fraction problems usually involve basic rules along with the concepts of part/whole and the 'rest'. Decimals are fractions and fractions can be decimals. When possible - convert decimals to fractions.






4. To add 2 or more fractions with the same denominator - simply add up the numerators and put the sum over the denominator - Example - 1/7 + 5/7 = (1+5)/7 = 6/7






5. It's easy to break the percentage down into chunks Example 20% of 60 = 10% of 60 = 6; 20% of 60 is double 10% = 2x6 = 12 Example 30% of 60 - 10% of 60 =; 30% is triple 10% = 3x6 = 18






6. 0.2 = 1/5 - 0.25 = 1/4 - 0.333 = 1/3 - 0.4 = 2/5 - 0.5 = 1/2 - 0.6 = 3/5 - 0.667 = 2/3 - 0.75 = 3/4 - 0.80 = 4/5






7. The 'whole' in a ratio is the sum of all its parts. If the ratio is expressed as a fraction - the whole is the sum of the numerator and denominator. Example - the ration of women to men in a room is 3 to 4. The ratio = 3 women / 4 men The fraction =






8. Just another way of expressing division - Example - 1/2 is equal to 1 divided by 2. Another important way to think of a fraction is as part/whole






9. To subtract 2 or more fractions with the same denominator - subtract the numerators over the denominator - Example - 6/7 - 2/7 = (6-2)/7 = 4/7






10. Close relatives of fractions. Can be expressed a fraction and vice versa. The ratio 3 to 4 can be expressed as 3/4.






11. To get 10% of any number - move the decimal point over one place Example - 10% of 6 = .6 ; 10% of 60 = 6






12. To multiply fractions - just multiply the numerators and put the product over the product of the denominators - Example - 2/3 x 6/5 = 12/15






13. Just a fraction in which the denominator is always equal to 100. Fifty percent means 50 parts out of a whole of 100. Like any fraction - a percentage can be reduced - expanded - cross multiplied - converted to a decimal or converted to a fraction.






14. You can compare fractions directly only if they have the same denominator. It is easiest to compare two fractions at a time. SHORTCUT = Bowtie = multiply denominator of 1st fraction by numerator of 2nd; denominator of 2nd fraction by numerator of th






15. The way to divide one decimal by another is to convert the number you are dividing by a whole number - you do this by simply moving the decimal point in the divisor as many places as necessary to get a whole number and you match this decimal point mo






16. Move the decimal point of that number over two places to the left Example - 1% of 600 = 6 ; 1% of 60 = .6






17. To ________________ - divide the interest into as many parts as are being compounded. For example - if you're compounding semiannually you divide the interest into two equal parts. If you're compounding quarterly - you divide the interest into four e






18. Before you add or subtract fractions with different denominators - you must make all the denominators the same. You must multiply by a fraction that is equal to 1 to keep the value the same - Example - 1/2 = 2/3 = 1/2x3/3 = 2/3x3/3 = 3/6 + 4/6 = 7/6






19. Just a different way to express a fraction. Example - In two boxes there are 14 shirts - how many shirts are in three boxes? - 2 (boxes)/14 (shirts) = 3 (boxes) / X shirts - then bowtie - 2X = 3 x 14 = 42; 42 / 2 = x; x = 21






20. To divide one fraction by another - just invert the second fraction and multiply - Example - 2/3 divided by 3/4 = 2/3 x 4/3 = 8/9






21. In any problem with a percent increase or decrease - the trick is to always put the increase or decrease in terms of the original amount. Example - House in 1980 was $120 -000; in 1988 the house is worth 180 -000. What is the percentage increase? *a






22. Simply ignore the decimal points - when you are finished - count all the digits that were to the right of the decimal point in original order multiplied. Example - 14.3 x .232 = 3.3176 (there were four decimal points in originally)






23. An integer can be expressed as a fraction by making the integer the numerator and making the denominator 1. Example - 16 = 16/1






24. To add or subtract decimals - just line up the decimal points and proceed. Example - 6 + 2.5 + 0.3 looks like 6.0 2.5 - 0.3 = 8.8