How many whole numbers are there with not more than 4 digits?

A digit is a symbol that is used to write numbers. We use the whole number digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. We can use these digits to write any number.

0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 are one digit numbers.

So total number of one digit number = 10

All the numbers from 10 to 99 are two digit numbers.

So total number of two digit numbers = 90

All the numbers from 100 to 999 are three digit numbers.

So total number of three digit numbers = 900

All the numbers from 1000 to 9999 are four digit numbers.

So total number of four digit numbers = 9 000

whole numbers are there with not more than 4 digits = 10 + 90 + 900 +9000 = 10,000

correct answer:

i^31 = -i

the answer would be d

straight away you can eliminate a and c because not all books contain a scientific skill because some may be fiction. c is also wrong because it saids that the only way children can learn is through books which is incorrect.

b is also wrong because reading can be a scientific skill but not always, therefore it is wrong which leaves you with d, the correct answer since it said that it can children learn.

hope this ! : 3