Eric's notebook has 30 pages he wants to number all the pages beginning with 1 how many digits will he write when he writes in his notebook

Answer 1

What do you think?

Answer 2

Numbers 1 ÷ 9 are one digits numbers.

Numbers 10 ÷ 30 are two digits numbers.

Obviously Eric will write 9 one digits numbers and 21 two digits numbers.

9 * 1 + 21 * 2 = 9 + 42 = 51 digits