Elementary Algebra

7.78 $\times$ $10^{11}$
We need to 778,000,000,000 as the product of a number greater than or equal to 1 and less than 10, and an integral power of 10. The number greater than or equal to 1 and less than 10 will be 7.78. The decimal point has moved 11 places, so the exponent of 10 will be 11. So, 778,000,000,000 = 7.78 $\times$ $10^{11}$