41
4/4 equals 1, so you can make practically any whole number from 4s. Just keep adding 4/4 together!
20 and 1
-4 x 5 = -20 and -4 + 5 = 1.
These are the prime numbers 1-20 2,3,5,7,11,13,17,19
(4s + 1)(4s + 1) or (4s + 1)2
20 and 1. 20 + 1 = 21 20 - 1 = 19
Cr [Ar] 4s^1 3d^5
The sum of the numbers from 1 to 20 inclusive is 220.
2/5 of the numbers from 1 to 20 are prime numbers
Factors go into numbers, numbers go into multiples. The factors of 20 are 1, 2, 4, 5, 10, 20 The multiples of 20 are 20, 40, 60, 80, 100 and so on.
The square numbers between 1 and 20 are 1,4,9 and 16.