Multiplication and factorization of all mathematical formulas in Grade 7 A2-B2 = (a+b) (a-b) A3+B3 = (a+b) (A2-AB+B2) A3-B3 = (a-b) (A2+AB+B2) Trigonometric Inequality | A+B |≤|+= & 0 Note: The equation has a real root B2-4ac 0 sector area formula s= 1/2*l*r cone volume formula V= 1/3*S*H cone volume formula V= 1/3*pi*r2h oblique prism volume V=S'L Note: where s' is 0 reading in front of each level. The zeros in the middle of each level, no matter how many zeros there are, are read-only. A cone is 1/3 cylinders. A cylinder is three times as big as a cone. The numerator is the same, and the smaller the denominator, the greater the score. The denominator is the same, and the bigger the numerator, the smaller the score. The numerator is above and the denominator is below. Encounter problem Encounter distance = speed and meeting time Meet time = Meet distance Sum of speed and speed = Meet distance Meet time Profit and discount problem Profit = Selling price-cost profit rate = Profit cost 100% = (Selling price cost-1) 100% Increase or decrease amount = percentage interest of principal increase or decrease = principal interest rate after tax = principal interest rate. -20%) length unit conversion 1 km = 1 000m1m = 1 decimeter =10cm/cm hectare =/kloc-0. Kloc-0/00 square decimeter 65438kg 1 kg = 1000g 1 kg RMB unit conversion 1 yuan = 10 angle1angle =10 minute. Yes:1\ 3 \ 5 \ 7 \ 8 \10 \ 65438+abortion in February (30 days): 4 \ 6 \ 9 \ 65438. Leap year 366 days 1 day =24 hours 1 hour =60 minutes 1 minute =60 seconds 1 hour =3600 seconds × number of copies = total number ÷ each copy = speed× time = distance ÷ speed. Working hours = total workload ÷ working efficiency = working hours ÷ total workload ÷ working hours = working efficiency addend+addend = and-one addend = another addend-minuend = difference-difference = minus+minus = minuend factor × factor = product ÷ one factor = dividend of another factor. Quotient = divisor quotient × divisor = dividend sum and multiple problem (sum+difference) ÷ 2 = large number (sum-difference) ÷ 2 = decimal sum ÷ (multiple-1) = decimal decimal × multiple = large number sum-decimal = large number difference multiple problem ÷ (. = decimal × multiple = large number decimal+difference = large number meeting problem meeting distance = speed and× meeting time = meeting distance ÷ sum of speed and speed = meeting distance ÷ meeting time profit and discount problem profit = selling price-cost profit rate = profit ÷ cost × 100% = (selling price ÷ cost ×