A.D1-D2 B.D1+D2 C.D1-M D.D1+M
A.2 B.3 C.4 D.5
A.LEFT("計算機",4)="計算" B.INT(3/2)=1 C.SUBS("computer",6,3)="TER" D."Ab"-"1995"="Ab1995"