Answer:
621200000000000000
Explanation:
(6.2×10^17 )+(1.2×10^15)
6.2×100000000000000000+1.2×10^15 ≈6.212⋅10^ 1 7
620000000000000000+1.2×10^15 ≈6.212⋅10^ 1 7
620000000000000000+1.2×1000000000000000≈6.212⋅10^ 1 7
620000000000000000+1200000000000000≈6.212⋅10^1 7
621200000000000000