Write a function that solves an algebraic expression given as a string. 
* The expression can include only sums and products. 
* The numbers in the expression are in standard notation (NOT scientific).
* In contrast, the function should return a string with the calculated value given in scientific notation with 5 decimal digits. 
# Example:
```python
strexpression = "5 * 4 + 6"
sum_prod(strexpression) = "2.60000e+01"
```
sum_prod=lambda ex:'{:.5e}'.format(sum(eval(i) for i in ex.split('+')))
sum_prod=lambda ex:'{:.5e}'.format(sum(eval(i) for i in ex.split('+')))