Python 2.x:

import math
int( math.floor( a ) )

N.B. Due to complicated reasons involving the handling of floats, the int cast is safe.

Python 3.x:

import math
math.floor( a )

Simplest way will be to type-cast the float value to int. For example:

>>> x = 100.0
>>> x = int(x)
>>> x
100

Hence, in your code you should do:

print("Teie nädalapalk on " + str(int(tunnid*tasu)))
# Note: "str(tunnid*tasu)" replaced with "str(int(tunnid*tasu))"

When a number as a decimal it is usually a float in Python.

If you want to remove the decimal and keep it an integer (int). You can call the int() method on it like so...

>>> int(2.0)
2

However, int rounds down so...

>>> int(2.9)
2

If you want to round to the nearest integer you can use round:

>>> round(2.9)
3.0
>>> round(2.4)
2.0

And then call int() on that:

>>> int(round(2.9))
3
>>> int(round(2.4))
2

To print Decimals without the 'Decimal' appearing, you could subclass Decimal and override __repr__:

>>> class MyDecimal(Decimal):
...   def __repr__(self):
...     return str(float(self))
...
>>> x = Decimal(4.1)
>>> x
Decimal('4.0999999999999996447286321199499070644378662109375')
>>> y = MyDecimal(5.3)
>>> y
5.3

However, when you do any operation with them, the repr goes back to it's original form:

>>> y = MyDecimal(5.3)
>>> z = MyDecimal(4.2)
>>> y + z
Decimal('9.500000000000000000000000000')

To always get MyDecimal in such cases, you would need to override all of Decimal's operations to return a MyDecimal obeject instead of Decimal.

Note that what we're seeing here is the representation of the decimal. And you will need to leave that as is when doing other operations. Or always convert to float when using it elsewhere. From the docs:

Decimal objects cannot generally be combined with floats in arithmetic operations: an attempt to add a Decimal to a float, for example, will raise a TypeError. There’s one exception to this rule: it’s possible to use Python’s comparison operators to compare a float instance x with a Decimal instance y. Without this exception, comparisons between Decimal and float instances would follow the general rules for comparing objects of different types described in the Expressions section of the reference manual, leading to confusing results.

With Python 3.6+ you should consider formatted string literals (PEP 498):

x = 8.5
y = 9.0
z = 8.05

for i in (x, y, z):
    print(f'{i:.9g}')

8.5
9
8.05

Manually, you can define a function to compare float and int values:

def make_str(x):
    float_val = float(x)
    int_val = int(float_val)
    if float_val == int_val:
        return str(int_val)
    return str(float_val)

make_str(9.0)  # '9'
make_str(8.5)  # '8.5'