# A simple association between letters and numbers

• $$X$$ is 5.
• $$U$$ is 9.
• $$O$$ is 0 or 7.
• $$I$$ is 4 or 5 or 7.

What is $$V$$? And what is $$K$$ (two options)?

• Inspired by this puzzle, but the underlying pattern is not the same. – Rand al'Thor Jun 9 at 20:42

I think that

$$V$$ is $$2$$
$$K$$ is $$1$$ or $$3$$

Reasoning

Find the elements in the periodic table whose chemical symbol begins with the letter. The associated numbers are those in the tens position of the corresponding atomic numbers.

Examples

$$X \rightarrow$$ is Xenon (Xe) whose atomic number is 54
$$U \rightarrow$$ Uranium (U) with atomic number 92
$$O \rightarrow$$ Oxygen (O) and Osmium (Os) with atomic numbers 08 and 76
$$I \rightarrow$$ Indium (In), Iodine (I) and Iridium (Ir) with atomic numbers 49, 53, 77
$$V \rightarrow$$ Vanadium (V) with atomic number 23
$$K \rightarrow$$ Potassium (K) and Krypton (Kr) with atomic numbers 19 and 36.

Note: Oganesson (Og) has not been included here, either it is too new or we are only considering elements less than 100.

• Brilliant! You got it. (I was expecting this one to be solved quicker - just came now to add a hint.) – Rand al'Thor Jun 13 at 8:09