Explanation:
The scientific notation:
[tex]a\times10^k[/tex]
where
[tex]1\leq a<10[/tex] and k is integer.
We have the example:
[tex](5\times10^3)+(4.3\times10^4)[/tex]
You can write the numbers in a "normal" form:
[tex]5\times10^3=5\times1000=5000\\\\4.3\times10^4=4.3\times10000=43000[/tex]
Make the sum:
[tex]5000+43000=48000[/tex]
And next write it in the scientific notation:
[tex]48000=4\underbrace{8000}_{\leftarrow4}=4.8000\times10000=4.8\times10^4[/tex]
Other method:
You can add numbers in scientific notation if the power of tens in both number is the same.
Therefore you must convert the first number:
[tex]5\times10^3=0.5\times10\times10^3=0.5\times10^4[/tex]
Now, you can make the sum:
[tex](5\times10^3)+(4.3\times10^4)=0.5\times10^4+4.3\times10^4=(0.5+4.3)\times10^4=4.8\times10^4[/tex]
