I really think you can do this.
13, 14, 15, 16, 17, 18, 19, 20...
Just count by three ... 3, 6, 9, 12 ,15, 18, 21, 24, 27 ... all the way to 99. There are 33 numbers in this list. 100 is not an even multiple of 3.
Exactly the same way you do when they're all whole numbers, or there are more than three numbers, or they're a mixture of whole numbers and decimals: -- Add up all the numbers on the list. -- Divide the big sum by the number of items on the list.
study hard
List the numbers from 2 to 100. Rows of 10 work well. Cross out all the multiples of 2 that are greater than 2. This will be the rest of the even numbers. Go to the next number that isn't crossed out (3) and cross out all of its greater multiples. Proceed in this fashion. Next up will be 5. You can stop when you get to fifty. The numbers that aren't crossed out are prime.
1+3+5+7+9+11 all the way to 100 = ?
Just count by three ... 3, 6, 9, 12 ,15, 18, 21, 24, 27 ... all the way to 99. There are 33 numbers in this list. 100 is not an even multiple of 3.
The sieve is just a method for finding primes. You write down the numbers 2 through n (lets say n = 100). And you go through the list crossing off numbers in a set way. You start with 2, and cross off 4,6,8,10, etc etc, all the way to 100. Then you go to 3, and cross off 6,9,12,15, etc all the way to 100. Then you go to the next number (four has already been crossed off when you did 2 so we're at 5 now), cross off 10,15,20,25, etc.. all the way to 100, etc etc etc through the list till you do the last one at n/2 (50). What you have in front of you now is a list of all the prime numbers from 2 to n (100), since everything else that is composite (not prime), has been crossed out.
Exactly the same way you do when they're all whole numbers, or there are more than three numbers, or they're a mixture of whole numbers and decimals: -- Add up all the numbers on the list. -- Divide the big sum by the number of items on the list.
Oh, dude, you want me to do math? Fine, fine. So, like, numbers divisible by 3 under 100 would be 3, 6, 9, all the way up to 99. There you go, a list of numbers that can be divided by 3 without breaking a sweat.
Calculator time! 7x1 = 7x2 = and all the way to 7x14 =
study hard
List the numbers from 2 to 100. Rows of 10 work well. Cross out all the multiples of 2 that are greater than 2. This will be the rest of the even numbers. Go to the next number that isn't crossed out (3) and cross out all of its greater multiples. Proceed in this fashion. Next up will be 5. You can stop when you get to fifty. The numbers that aren't crossed out are prime.
1+3+5+7+9+11 all the way to 100 = ?
-99
To find the greatest common factor (GCF) you can use one of a few methods. One way (which i think is the hardest) you list all the factors of those two numbers. Another way is to just multiply the numbers together. Now, if you have big numbers, these steps might be a little complicated or harder to do, but if you want to list all the factors of that number, go right ahead.
There are 333 of them ... way too many to list here. But you can easily construct the list for yourself. Just write down all the numbers from ' 3 ' to ' 999 ' on paper. Then go like this: -- Circle the first number. -- Cross out the next two numbers. -- Circle the next number. -- Cross out the next two numbers. -- Circle the next number. -- Cross out the next two. Keep going like this, all the way down the list. When you're finished, you have 333 numbers circled. Those are all the multiples of ' 3 ' up to 1,000.
least to greatest