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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. 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.






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. 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






4. 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






5. 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






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






7. 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






8. 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)






9. 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






10. 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






11. 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






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






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






14. 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.






15. 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






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






17. 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






18. 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






19. 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 =






20. 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






21. 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






22. 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






23. 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






24. 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