0
The number that has 7 tens and less ones than tens is 70 minus a certain number of ones. Since there are 7 tens, which is 70, and it needs to have less than 7 ones, the possible values for the ones place are 0 through 6. Therefore, the possible numbers are 70, 71, 72, 73, 74, 75, and 76.
You can be 96, 85, 74, 63, 52, 41, and 30.
3
All but the number five are multiples of 5.
There are many number systems. The real numbers, the rational numbers, the complex numbers and some more esoteric ones such as p-adic numbers are all number systems.
10 or 5
The number that has 7 tens and less ones than tens is 70 minus a certain number of ones. Since there are 7 tens, which is 70, and it needs to have less than 7 ones, the possible values for the ones place are 0 through 6. Therefore, the possible numbers are 70, 71, 72, 73, 74, 75, and 76.
The ones with less than three factors.
You can be 96, 85, 74, 63, 52, 41, and 30.
3
3
You look for a table of prime numbers. Or you try out each integer from 2-100, to see which ones don't have smaller factors. For numbers less to 100, it is enough to check whether each number is divisible by 2, 3, 5 and 7.
34,24,23,14,13, or even 12.
It is an odd number, If you are going to answer these type of questions in the future, you just find the ones place, if the ones have the number 1,3,5,7 or 9 in them it is odd, and if the ones have the numbers 2,4,6 or 8 in them it is even. Hope I helped :)
The ones digit in the product from multiplying the 305 prime numbers less than 2012 is 0 because the ones digit becomes 0 after 2 and 5 have been multiplied and remains unchanged after more prime numbers are multiplied.
72 has two ones.
40, 51, 62, 73, 84, and 95