If base is different and exponential term is same, then take exponential term as common and add base and then multiply with common exponential term.
If base and exponential term both are different, then convert that number into same exponential term similar to other number. Then again repeat the step 1.
Addition for the scientific notation 4×105 and 3×105 ?
So this will be = (4+3)×105
We took 105 common from both notation.
Addition for the scientific notation 3.557×105and 8.0039×108 ?
First we have to convert the common exponent
The lesser exponent(5), which have to be increased by 3.
So, 3.557×105 = 0.003557×108