### Question

Why am I seeing extra decimal places being outputted when doing basic arithmetic in Python, and how can I round those numbers?

### Answer

A loss in precision often occurs when doing floating point arithmetic. This is due to the nature of floating point numbers and how they are stored in the machine (*see here for more details*). For example, the below will print `0.44999999999999996`

instead of `0.45`

:

```
sum = 0.1 + 0.35
print(sum) # 0.44999999999999996
```

A couple ways you could round your final answer is to use the built-in `round()`

function or to format the answer as a string using the string method `.format()`

:

```
print(round(sum, 2)) # 0.45
print('{:.2f}'.format(sum)) # 0.45
```