1.a) 3 x (45+15)=3 x 60= 180
b) 20 x (48+2)=20x50=1000
c)28 x (521-21)=28 x 500=14000
d)23 x(718-23)= 23 x 695=15985
e)15 x (38+162)= 15 x 200=3000
f)702 x (65-35)=702 x 30=21060