Convert between scientific notation and ordinary numbers. only do the circled questions

Two would be 2.9x10^8.
Three would be 2.84x10^6.
Four would be 6.398x10^5.
Six would be 9.784x10^7.
Seven would be 1.9x10^5.
Eight would be 8.74x10^5.
Nine would be 2.9x10^4.
Ten would be 2.065x10^3.
Eleven would be 1.17x10^3.
Thirteen would be 0.8430x10^-1.
Sixteen would be 7.8x10^3.
Eighteen would be 8.1x10^6.

I’d say letter a..