1. a) 120 075= 100000*1 + 10000*2 + 10*7 + 5
b)120 075: 15= 8005
c)120 075 < 120 078
2. a) 25* ( 34+26) = 25* 60= 1500
b) (63-42)*2= 21*2= 42
c)150 150 - 150 x [19*2 - (15*2+5*3)]=
150 150 - 150 x [361- (225+125)]=
150 150 - 150 x (361 - 350)=
150 150 - 150 x 11=
150 150 - 1650= 148 500
