GMAT QUANTITATIVE REASONING – MATH| 57 QUESTIONS AND ANSWERS

a + b = b + a a x b = b x a (a + b) + c = a + (b + a) (a x b) x c = a x (b x a) a (b + c) = ab + ac Adding a positive number Move right along the number line Subtracting a positive number Move left along the number line Adding a negative number Move left along the number line a + (-b) = a - b Subtracting a negative number Move right along the number line a - (-b) = a + b 1/2 0.5 1/3 0.333 1/4 0.25 1/5 0.2 1/6 0.1666... 1/7 0.14 1/8 0.125 1/9 0.11 n = n/1 n/0 undefined n/n 1 1/a/b b/a a/b x b/a = 1 bigger numerator bigger value smaller numerator smaller value bigger denominator smaller value smaller denominator bigger value fraction approaches 1 increase numerator and denominator by same amount abc/def = a/d + b/e x c/f a + b/c = a/c + b/c a/b x b = a a/b = c/d ad = bc part/whole = percent/100 p percent of x is y (p/100)(x) = y % change change x 100/ original value new change (1 + percent change/100) x original compound interest = P (1 + r/c)^nc compound interest P Principle compound interest r annual interest rate Compound Interest c number of "compoundings" per year compound interest n number of years simple interest (principle)(rate)(time) a:d = b:c a/b = c/d Positive base x 1 the value of x^n increases as n increases Positive base 0 x 1 the value of x^n approaches zero as n increases negative base x -1 the value of x^n increases as n increases but the sign oscillates negative base -1 x 0 the value of x^n decreases as n increases 75^2 = 7 x 8 = 56 5^2 = 25 5625 105^2 = 10 x 11 = 110 5^2 = 25 11025 x^a/x^b = x^a-b (x^a)(x^b) = x^a+b (x^a)^b = x^ab x^-n = 1/x^n (a/b)^-n = (b/a)^n