How many numbers between 200 and 400 begin or end in 3?

Answer 1

To find the numbers between 200 and 400 that begin or end in 3, we can break it down into two parts. The numbers beginning with 3 range from 300 to 399, which gives us 100 numbers. For numbers ending with 3, we have 203, 213, 223, ..., 393, which gives us 20 numbers (one for each ten from 200 to 390). However, we need to avoid double-counting 303, so the total is 100 + 20 - 1 = 119. Thus, there are 119 numbers between 200 and 400 that begin or end in 3.