def double(sequence):
    result = []
    for element in sequence:
        result = result + [element*2]
    return result

double([1,10,5]++)

  File "/tmp/ipykernel_8229/1792737275.py", line 1
    double([1,10,5]++)
                     ^
SyntaxError: invalid syntax

double([1,10,5])

[2, 20, 10]

double([-42,0,42])

[-84, 0, 84]

double([24])

[48]

double([])

[]

double()

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
/tmp/ipykernel_8229/2608569975.py in <module>
----> 1 double()

TypeError: double() missing 1 required positional argument: 'sequence'

double means that the calculator doubles the amount/number contained in the squared brackets

x=[1,2,3]

double(x)

[2, 4, 6]

double(5)

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
/tmp/ipykernel_8229/1555949217.py in <module>
----> 1 double(5)

/tmp/ipykernel_8229/838696399.py in double(sequence)
      1 def double(sequence):
      2     result = []
----> 3     for element in sequence:
      4         result = result + [element*2]
      5     return result

TypeError: 'int' object is not iterable

triple(5)

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
/tmp/ipykernel_8229/1069537581.py in <module>
----> 1 triple(5)

NameError: name 'triple' is not defined

thrice([5])

x=[1,2,3]

double(3x)

  File "/tmp/ipykernel_8229/4268276446.py", line 1
    double(3x)
            ^
SyntaxError: invalid syntax

def thriple (sequence):
    result = []
    for element in sequence:
        result=result+[element*3]
    return result

thriple([1,2,3])

[3, 6, 9]

def half (sequence):
    result=[]
    for element in sequence:
        result=result+[element/2]
    return result

half([8,10,12])

[4.0, 5.0, 6.0]

def squared (sequence):
    result=[]
    for element in sequence:
        result=result+[element*element]
    return result

squared([2,4,5])

[4, 16, 25]

4+4.5+0.375

8.875

1500*0,08875

  File "/tmp/ipykernel_8229/1334303866.py", line 1
    1500*0,08875
               ^
SyntaxError: invalid token

1500*0.08875

133.125

995.50*0.08875

88.350625

def tax(subtotal):
    return subtotal*0.08875