Adding with same denominator (a/b)+c/b)=((a+c)/b) Subtracting with same denominator (a/b)-(c/b)=((a-c)/b) Adding with different denominator (a/b)+(c/d)=((ad)+(cb))/bd Subtracting with different denominator (a/b)-(c/d)=((ad)-(cb))/bd Multiplying Factors (a/b)(c/d)=(ac)/(b*d) Dividing Factors (a/b)/(c/d)=(ad)/(bc) Factoring numbers a(c/d)= a+(c/d)= (ad+c)/d Intergers {...,−3,−2,−1,0,1,2,3,...} Real Numbers All numbers that are on number line. Integers plus fractions, decimals, and irrationals PEMDAS Parentheses, Exponents, Multiplication, Division, Addition, Subtraction Percentages part = (percent / 100) x whole percent of change ((New value - old value)/old value) X 100 Distance from A to B √(x2 − x1)^2 + (y2 − y1)^2 Parallel and Perpendicular lines Parallel lines have equal slopes. Perpendicular lines (i.e., those that make a 90∘90° angle where they intersect) have negative reciprocal slopes: ????1m1 .????2=−1m2=−1.Parallel Lines (l ∥∥ m) Mid-point of the segment AB M (????1+????2/2),(????1+????2/2)