How do you wright twelve and a half trillion in scientific notation?

The correct answer is:

Explanation:

First we must determine where the trillions place is in place value. The first group of 3 digits is thousands; the second group of 3 is the millions; the third group of 3 is the billions; and the 4th group of 3 is the trillions. This means that 1 trillion would be a 1 with 12 zeros following it.

This means that 12 trillion would be 12 with 12 zeros following it. The "half" would be a 5 immediately after the 12, which would give us

12,500,000,000,000

Scientific notation requires 1 non-zero digit in front of the decimal. This means we would have 1.25. The exponent of 10 is the number of decimal places we must move the decimal; for this number, that is 13 places. This gives us