Question

How many three digit numbers are there such that at least one of the digits is 4?

Answer 1

Answer:

252

Step-by-step explanation:

when none of the digits is 4

hundred place can be filled in 8ways

tens place in 9 ways

ones place in 9 ways

total = 8×9×9=648

total 3 digit number= 9×10×10=900

Numbers with atleast one of the digits as 4 = 900-648= 252

Answer 2

Answer:

104, 204,...,904 = 9

114, 214,…,914 = 9

124,…,924 = 9

134,…,934 = 9

140,141,…149,…949= 9×10 =90

154,…954 = 9

164,…,964 = 9

174,…,974=9

184…984=9

194 …994=9

total= 171