## Exercise 1.1
```python
def zorglub(n: int) -> int:
	j = 1
	k = 0
	i = 1
	while i <= n:
		j = i * j
		k = j + k
		i = i + 1
	return k
```

The function return the sum of the factorial of n

## Exercise 1.2
```python
def multiplication(x: int, y: int) -> int:
	result = 0
	while y > 0:
		m += x
		y -= 1
	return result


def multiplication2(x: int, y: int) -> int: # Thanks Hugo :p
	if y < 0:
		y = -y
		if x < 0:
			return multiplication(-x, y)
		return -multiplication(x, y)			
	else
		return multiplication(x, y)

def productZ(x, y):
	pos = True
	if x < 0:
		x = -x 
		pos = False
	if y < 0:
		y = -y
		pos = not pos
	m = multiplication(x, y)
	if not pos:
		m = -m
	return m
```

## Exercise 1.3
```
def exponetial(x: int, n: int) -> int:
	result = 0
	while n > 0:
		m *= x
		n -= 1
	return result

def power(x, n):
	if x == 0;
		if n == 0:
			raise Exception("0 power 0 undefinded")
		else:
			return 0
	elif x == 1:
		return 1
	elif x == -1:
		return (n%2)*(-2) + 1
	else:
		res = 1
		while n > 0:
			res *= x
			n -= 1
		return res
```

## Exercise 1.4

```python
def fibo(n):
	prev = 1 #f0
	cur = 1 #f1
	while n> 1:
		(prev, cur) = (cur, prev+cur)
		n -= 1
	return cur
# OR

```

## Exercise 1.5
```python
def my_sum(n: int) -> int:
	s = 0
	i = 1
	while i <= n:
		s += u(i)
		i += 1
	return s
# OR

def my_sum(n: int) -> int:
	s = 0
	while n > 0:
		s += u(n)
		n -= 1
	return s