A1/b1/c1/d1/e1are the date/payment amount/current payment amount/next payment amount/remarks respectively.

C2 = If (b2 <: 20000, B2, if (B2 <; =50000，0，B2/2))

D2=B2-C2

E2 = IF(B2 & lt； 20000, "cash payment", if (B2