If you mean that the sum of two consecutive numbers should be 257, here are two ways to solve it:
1) Trial and error. Just try out different numbers; if the sum is too large, try again with smaller numbers; if the sum is too small, try again with larger numbers.
2) With algebra, you can get the result faster. Call the first number "x", then the second number is "x + 1". Thus, you get the equation:
x + (x + 1) = 257
Solve this for "x", and you get the first of the two consecutive numbers.
The consecutive numbers that have a sum of 257 are 128 and 129.
259
257/2 = 128.5 so 128 and 129
128.5 if you're talking about consecutive numbers.
256, 257, 258 Let the three numbers be n-1, n, n+1, then: (n-1) + n + (n+1) = 771 → 3n = 771 → n = 257 → the three numbers are 257-1 = 256, 257 and 257+1 = 258
4,5
255 and 257
2 and 3 are consecutive prime numbers.
2 and 3 are consecutive numbers and they are both prime.
The numbers 2 and 3 are consecutive prime numbers. Are there other pairs of prime numbers which are consecutive numbers?
The only consecutive prime numbers are 2 and 3.
The numbers are 54 and 56.