Final answer:
The correct numeral for seventy million is 70,000,000. In scientific notation, this is expressed as 7.0 × 10⁷.
Step-by-step explanation:
The correct way to write seventy million as a numeral is 70,000,000. When dealing with large numbers, the placement of commas is important to denote the value correctly.
In the United States, commas are placed every three digits when writing numerals to make them easier to read.
To express numbers in scientific notation, you move the decimal point so that only one non-zero digit remains to the left of it, then multiply by a power of ten that corresponds to the number of places you moved the decimal.
For example, 70,000,000 becomes 7.0 times 10 to the seventh power, or 7.0 × 107.