Question

Calculati dand factor comun :

a). 1992+1993×1992-1994×1991
b). (111+222+.......+666):111×21

Answer 1

a) 1992(1+1993)-1994*1991=
1992*1994-1994*1991=
1994(1992-1991)=
1994*1=1994

b) 111(1+2+3+4+5+6):111*21=
(1+2+3+4+5+6)*21=
6*7/2*21=
21*21=
21^2=441