Answer: [tex]5.21 \times 10^7 = 52,100,000[/tex]
This number is slightly larger than 52 million.
To get this answer, we move the decimal point 7 spaces to the right to go from 5.21 to 52,100,000.
The positive exponent means "move right that amount of spaces". If the exponent was negative, then you'd move left that amount of spaces.
