If you assume that each side shares a corner post then it takes 12 fence posts.
Answer:
When it crosses y-axis it means that x coordinate must be 0 so let substitute 0 to x, y=5-2*0
So coordinates are [0,5]
Addition, subtraction, multiplication.
Addition: The addition of two integers produces another integer.
Subtraction: The subtraction of two integers produces another integer.
Multiplication: The product of two integers is an integer.
Division between two integers can produce a rational number that is not in the set of integers e.g. 1/3
This only includes the four basic arithmetic operations, you can include exponentiation and the modulo operation if you want to for the same reasons as above.
