Question

How many positive integers less than 1,000 do not have 7 as any digit?

Answer 1

Calculate the numbers that do have 7 in it.
1 to 10 :1
70 to 79:10
1 to 100:1×9+10=19
700 to 799:100
1 to 999:8×19+100=252

intergers with no 7=999-252=747