1, a (fixed cost): refers to the part of the cost whose total amount does not change with the business volume within a certain relevant range. 2. B (variable cost): refers to the part of the cost whose total amount changes in direct proportion to the business volume within a certain relevant range. 3. Cost behavior model: y=a+bx4, operating profit difference = operating profit under absorption costing-operating profit under variable cost method 5, Simplified calculation formula of operating profit difference: operating profit difference = fixed manufacturing expenses absorbed by absorption costing's next ending inventory-fixed manufacturing expenses released by absorption costing's next ending inventory = fixed manufacturing expenses of absorption costing's next ending inventory × ending inventory-fixed manufacturing expenses of absorption costing's next ending inventory × opening inventory 6. Basic formula for profit calculation: P=px-bx-a7, Correlation formula of contribution margin: total contribution margin Tcm= px-bx, unit contribution margin cm= p-b, contribution margin cmR=cm/p, Variable cost rate bR=b/ p bR+cmR=18, breakeven point analysis capital preservation amount x1=a/ cm= a/ (p-b) capital preservation amount y1= a/ cmR= p x19, Formulas related to safety editing: safety margin MS = actual or estimated sales volume-guaranteed amount safety margin MS = actual or estimated sales volume-guaranteed amount safety margin MSR= MS (amount)/actual or estimated sales volume (amount) guaranteed operation rate dR= guaranteed amount (amount)/ Actual or estimated sales volume (amount) MSR+ dR=1 Profit = contribution margin × safety margin 11, poly point analysis poly amount x'=a+TP/ cm= a/ (p-b) poly amount y' = px' = a+TP/CMR = a+TP/(1–br) 11, Comprehensive contribution margin rate (CMR') = ∑ (CMRI Bi) Bi represents the sales proportion of I products 12, operating leverage coefficient (DOL)= profit change rate/production and sales change rate = contribution margin in base period/base period profit = cm x/ P Predicted profit P2= P1×(1+ change rate of production and sales ×DOL) Predicted sales X2=X1×(1+ change rate of profit /DOL)13, contribution margin per unit resource = contribution margin per unit product resource consumption quota 14, Analysis steps of differential profit and loss method: (1) differential income △R=RA-RB (2) differential cost △C=CA-CB (3) differential profit and loss △P=PA-PB15, cost indifference point X1=(a1-a2)/(b2-b1)16, project calculation period (n) = construction period+. Original value of fixed assets = investment in fixed assets+capitalized loan interest during construction period 18. Net cash flow NCFt ＝CIt- COt Simplified formula: NCFT during construction period =-NCFT during IT production and operation period = PT+DT+MT+CT+RTPT is the profit of the t year; Dt is the depreciation amount in the t year; Amortization amount of Mt in t year; Ct is the interest expense charged in the financial expense in the t year; Rt is the amount recovered in the t year. 19, compound interest present value coefficient (p/f, I, n) = (1+I)-N21, compound interest final value coefficient (f/p, I, n) = (1+I) N21, ordinary annuity present value coefficient (pa/a, I, n) = [1-(1+I). Is to convert the annual net cash flow into the present value NPV = ncf1× (p/f, I, 1)+ncf1× (p/f, I, 1)+...+ncfn× (p/f, I, n) 24, internal rate of return (IRR), which refers to the actual expected rate of return of project investment, that is, the investment project can be made. Calculation steps: 1) Step-by-step approximation method (step-by-step test method) uses interest rate i1 to calculate and get NPV1, if NPV 1 >; 1, increase the calculation ratio i2, the difference between the two interest rates is less than 5%, and NPV2 is obtained after calculation. If NPV2 >; 1, continue to improve the ratio calculation, until the difference between the two interest rates is less than 5%, and one NPV >; 1, an NPV <; 1, and then you can use interpolation; On the other hand, reduce the calculation ratio and calculate NPV 2) The application of interpolation method assumes that two NPVs are obtained through calculation, and the corresponding values are as follows: i1-NPV 1, I2-NPV2 (in line with the condition △ I <; 5%，NPV1> 1，NPV2< 1）IRR= i1+ NPV1/（NPV1- NPV2）×（i1- i2）25、 Calculation and analysis of cost variance Total cost variance = actual price × actual consumption × actual output-standard price × standard consumption × actual output Price variance = (actual price-standard price) × actual consumption × actual output consumption variance = standard price × (actual consumption-standard consumption) × actual output If direct material cost variance analysis is involved: Total direct material cost variance = actual direct material price × actual direct material consumption. —Standard price of direct material × standard consumption of direct material × actual output Direct material price difference = (actual price of direct material—standard price of direct material )× actual consumption of direct material × difference of actual output Direct material consumption = standard price of direct material × (actual consumption of direct material—standard consumption of direct material )× actual output If direct labor cost difference analysis is involved: the price is changed to wage rate, The total difference of direct labor cost from consumption to working hours = actual wage rate × actual working hours × actual output—standard wage rate× standard working hours× actual output wage rate difference = (actual wage rate—standard wage rate) × actual working hours× actual output labor efficiency difference = standard wage rate × (actual working hours—standard working hours )× actual output 26, economic batch (q *) = (2ap/c).