2
1000
90. all the numbers from 10 through 99
four, five, nine :)....and zero
The number line from 1 to 10 includes 10 integers, but an infinite number of real numbers.
There are 10 square numbers
The answer is 20C10 which is 20!/[10!(20-10)!] = 184756
When you spell out the words for numbers 1-10 four of the numbers have three letters. (one two six ten)
1000
90. all the numbers from 10 through 99
four, five, nine :)....and zero
3. Three, Seven, Eight.
Only the number 8 (VIII)
3 This are Three, Seven, and Eight.
The number of combinations of 7 numbers from 10 is 10C7 = 10*9*8/(3*2*1) = 120
109
Infinitely many. In fact there are more irrational numbers between 1 and 10 than there are rational numbers - in total!
The digit "1" appears in the numbers from 1 to 100 a total of 21 times. It appears once in each of the numbers 1 through 9, in the tens place for the numbers 10 through 19 (10 times), and once in the number 21. Therefore, counting all occurrences, it sums up to 21.