GRE Quantitative Reasoning Prep
EVEN + EVEN = - EVEN
EVEN - EVEN = - EVEN
EVEN + ODD = - ODD
EVEN - ODD = - ODD
ODD + ODD = - EVEN
ODD - ODD = - EVEN
ODD × ODD = - ODD
EVEN × ODD = - EVEN
EVEN × EVEN = - EVEN
LEAST COMMON MULTIPLE - THE LEAST POSITIVE INTEGER THAT IS A MULTIPLE OF
BOTH A AND B. FOR EXAMPLE, THE LEAST COMMON MULTIPLE OF 30 AND 75 IS 150.
THIS IS BECAUSE THE POSITIVE MULTIPLES OF 30 ARE 30, 60, 90, 120, 150, 180,
210, 240, 270, 300, ETC., AND THE POSITIVE MULTIPLES OF 75 ARE 75, 150,
225, 300, 375, 450, ETC. THUS, THE COMMON POSITIVE MULTIPLES OF 30 AND 75
ARE 150, 300, 450, ETC., AND THE LEAST OF THESE IS 150.
GREATEST COMMON DIVISOR (OR GREATEST COMMON FACTOR) - THE GREATEST
POSITIVE INTEGER THAT IS A DIVISOR OF BOTH A AND B. FOR EXAMPLE, THE GREATEST
COMMON DIVISOR OF 30 AND 75 IS 15. THIS IS BECAUSE THE POSITIVE DIVISORS OF
30 ARE 1, 2, 3, 5, 6, 10, 15, AND 30, AND THE POSITIVE DIVISORS OF 75 ARE 1, 3,