Example 0.2.1.

These are statements (in fact, atomic statements):

• Telephone numbers in the USA have 10 digits.

• The moon is made of cheese.

• 42 is a perfect square.

• Every even number greater than 2 can be expressed as the sum of two primes.

• \(\displaystyle 3+7 = 12\)

And these are not statements:

• Would you like some cake?

• The sum of two squares.

• \(1+3+5+7+\cdots+2n+1\text{.}\)

• Go to your room!

• \(\displaystyle 3+x = 12\)