number of +ve integers divisible by 2 less than or equal to 210=a=210/2=105
number of +ve integers divisible by 3 less than or equal to 210=b=210/3=70
number of +ve integers divisible by 7 less than or equal to 210=c=210/7=30
number of +ve integers divisible by 2&3 less than or equal to 210=d=210/6=35
number of +ve integer divisible by 2&7 less than or equal to 210=e=210/14=15
number of +ve integer divisible by 3&7 less than or equal to 210=e=210/21=10
number of +ve integer divisible by 2&7&3 less than or equal to 210=e=210/42=5
number of positive integers not larger than 210 and divisible by 2, 3 or 7=105+70+30-(35+15+10)+5
=150
so numbers not divisible=total-150
=210-150
=60