Scientific notation means representing something as a number on (0,10) exclusive, with a power of ten. Example: 47,573,018 would be 4.7573018 x10^7 Your numbers 20,000 and 3,400,000 can be represented as 2x10^4 and 3.4x10^6 You can bring these together by changing them so they have the same power of ten, rounding down. => 2x10^4 + 340x10^4 => 342x10^4 => 3.42x10^6 Final answer: 20,000+3,400,000=3.42x10^6 Hope I helped :)