Jack really likes his number five: the trick here is that you have to multiply each number by 5 raised to the number of digits of each numbers, so, for example:
```python
multiply(3)==15
multiply(10)==250
multiply(200)==25000
multiply(0)==0
multiply(-3)==-15
```

Difficulty: introductory

Starter code:

def multiply(n):
	

Solutions:
def multiply(n):
  return n*5**len(str(abs(n))) 

def multiply(n):
    return 5 ** len(str(abs(n))) * n

multiply=lambda n: n*5**len(str(abs(n)))

def multiply(n):
    return n * 5 ** number_of_digits(n)


def number_of_digits(n: int):
    return 1 if -10 < n < 10 else 1 + number_of_digits(n // 10)

def multiply(n):
    return n * 5 ** int_len(n)

def int_len(n):
    n = abs(n)
    length = 0
    while n:
        length += 1
        n //= 10
    return length

from math import log10
def multiply(n):
    return n*5**int(log10(abs(n))+1) if n!=0 else 0


import math

def multiply(n):
  dig_count = int(math.log10(abs(n)) + 1) if n else 1
  return n * 5**dig_count

def multiply(n: int) -> int:
    """ Multiply each number by 5 raised to the number of digits of each numbers. """
    return n * pow(5, len(str(abs(n))))

def multiply(n):
    nDigits=len(str(abs(n)))
    print(nDigits)
    return n*(5**nDigits)

def multiply(n):
    n = str(n)
    if int(n) < 0:
        return int(n) * 5 ** (len(n) - 1)
    else:
        return int(n) * 5 ** (len(n))

def multiply(n):
    for x in range(len(str(n))):
        n *= 5
    return n if n > 0 else n/5


def multiply(n):
    return n*5**(len(str(n)) - (1 if n < 0 else 0))

def multiply(n):
    #your code here
    return n * 5 ** len([i for i in str(n) if i.isdigit()])

def multiply(n):
    return n * 5**(len(str(n).replace('-','')))

def multiply(n):
    s = str(n).lstrip('-')
    return n * 5 ** len(s)

def multiply(n):
    s=str(n)
    factor=len(s)
    
    if n>0:
        return n*5**factor
    else:
        return n*5**(factor-1)

def multiply(n):
    i = 10
    j = 1
    while True:
        if abs(n) < i:
            return n*5**j
        else:
            i *= 10
            j += 1

def multiply(n):
    return n*5**(len(str(n)) if n>0 else len(str(n))-1)

import math
def multiply(n):
    if n > 0:
        digits = int(math.log10(n))+1
    elif n == 0:
        digits = 1
    else:
        digits = int(math.log10(-n))+2
        
    if n > 0:
        return 5**digits*n
    else:
        return 5**(digits-1)*n

def multiply(n):
    for x in range(1, len(str(abs(n)))+1):
        n*=5
    return n

def multiply(n):
    x = len(str(n).lstrip('-').replace('.',''))
    return n * (5**x)


def multiply(n):
    return n*pow(5, len(str(n))-1) if n < 0 else n*pow(5, len(str(n)))

def multiply(n):
    if n >= 0:
        a = str(n)
        return n * 5**len(a)
    elif n < 0:
        a = str(n)
        return n * 5**(len(a)-1)


def multiply(n):
    m = 5**(len(str(n))) if n>=0 else 5**(len(str(-n)))
    return n*m

def multiply(n):
    n_multiply = len(str(n).strip("-"))
    for i in range(n_multiply):
        n = n * 5
    return n

def multiply(n):
    print(len(str(n)))
    return n*5**len(str(abs(n)))

def multiply(n):
    return n * 5**(len(str(n if n > 0 else n * -(1))))


def multiply(n):
    return n * 5 ** len(str(n)) if str(n)[0] != "-" else n * 5 ** (len(str(n)) - 1)

def multiply(n):
    res = 5 ** len(str(abs(n))) * abs(n)
    
    return res if n > 0 else -res


def multiply(n):
    m=len(str(abs(n)))
    return 5**m*n

def multiply(n):
    m = len(str(n)) if n > 0 else len(str(n))-1 
    return n * 5 ** m

def multiply(n):
    if '-' in str(n):
        i = len(str(n)) - 1
    else:
        i = len(str(n))
    return n * (5 ** i)

def multiply(n):
    l = len(str(n))
    if n == 0:
        return 0
    if n > 0:
        return n*(5**l)
    if n < 0:
        return n*(5**(l-1))

def multiply(n):
    if n == 0:
        return 0
    elif n > 0:
        exp = len(str(n))
        return n * (5 ** exp)
    else:
        exp = len(str(-n))
        return n * (5 ** exp)

def multiply(n):
    if n < 0:
        x = str(n).replace('-','')
        y = len(x)
        return n * (5**y)
    else:
        return n * (5**len(str(n)))

multiply = lambda N,X=5:N*X**(len(str(N)[1 if N<0 else 0:]))

import math

def multiply(n):
  dig_count = math.floor(math.log10(abs(n))+1) if n else 1
  return n * 5**dig_count

def multiply(n):
    r=len(str(abs(n)))
    return n*5**r

def multiply(n):
    nd= len(str(n))
    for i in range(nd):
        n *= 5
    return n if n > 0 else n // 5

def multiply(n):
    return n * 5 ** len(str(n)) if n > 0 else n * 5 ** (len(str(n * -1)))

def multiply(n):
    return 5 ** len(str(n)[1:]) * n if str(n).startswith('-') else 5 ** len(str(n)) * n

def multiply(n):
    account = 0
    for value in str(abs(n)):
        account += 1
    return n*(5**account)


def multiply(n):
    if n<0:
        n = n*(-1)
        return -(5**len(str(n))*n)
    return (5**len(str(n))*n)

import math

def multiply(n):
    return n * 5**(int(math.log10(abs(n)))+1) if n else 0

def multiply(n):
    print(n)
    return (5**len(str(n)))*n if n>0 else (5**(len(str(n))-1))*n

def multiply(n):
    l = len(str(n)) if n >= 0 else len(str(n)) - 1
    return n *  (5 ** l)

def multiply(n):
    a=len(str(n))
    if n>0:
        return n*(5**a)
    else:
        return (n*(5**(a-1)))

def multiply(n):
    minus = False
    if n < 0:
        minus = True
        n *= -1
    n *= 5 ** len(str(n))
    if minus:
        n *= -1

    return n

def multiply(n):
    count = len(str(n))
    if n >= 0:
        return n * 5 ** count
    else:
        return n * 5 ** (count -1)
        
    


def multiply(n):
    return n * (5 ** len(list(str(n)))) if n > 0 else n * (5 ** len(list(str(n*-1))))

def multiply(n):
    l = len(str(n))
    return n * (5**l) if n > 0 else n * (5 ** (l-1))

def multiply(n):
    absolute = abs(n)
    new = str(absolute) 
    length = len(new)
    integer = int(length)
    return n * 5 ** integer

def multiply(n: int):
    return n * 5 ** len(str(abs(n)))

def multiply(n):
    n = str(n)
    if int(n) >=0:
        l = len(n)
    else:
        l = len(n) - 1
    n = int(n)
    return n*(5**l)

def multiply(n):
    #your code here
    if n>=0:
        
        b=5**len(str(n))
        return (n*b)
    elif n<0:
        n=abs(n)
        b=5**len(str(n))
        return -abs(n*b)

def multiply(n):

    l = len(str(n))
    lm = len(str(n)) - 1
    
    if str(n).startswith('-'):
        return n * 5**lm
    else:
        return n * 5**l

def multiply(n):
    if n > 0:
        multiplier = 5 ** len(str(n))
        operation = n * multiplier
        return operation
    else:
        convert = abs(n)
        mn = 5 ** len(str(convert))
        on = n * mn
        return on


def multiply(n):
    c = 0
    if n<0:
       c = c-n
       m = str(c)
    else:
       m = str(n)
   
    return n * 5**len(m)

def multiply(n):
    a=str(n)
    l=[]
    d=5
    for x in a:
        l.append(x)
    if(n>0): 
       for x in range(0,len(l)):
          n=n*5
    if(n<0):
       for x in range(0,len(l)-1):
          n=n*5
       
    return(n)

import math

def multiply(n):
    length = len(str(abs(n)))
    return n*5**length

def multiply(n):
    if n<0:
        n = -n
        return -n*5**len(str(n))
    else:
        return n*5**len(str(n))

def multiply(n):
    power = len(str(n))
    if n > 0:return n*(5**power)
    if n < 0: power = len(str(n)) - 1; return n*(5**power)
    else: return 0

def multiply(n):
    a = []
    if n < 0:
        a2 = str(n)
        a3 = (len(a2))
        a4 = a3 - 1
    if n > 0:
        d = str(n)
        c = (len(d))
    if n == 0:
        return 0
    elif n < 0:
        return (5 ** a4) * n
    elif n > 0:
        return (5 ** c) * n
    


def multiply(n):
    #your code here
    return n * 5 ** len(list(filter(str.isdigit,str(n))))

def multiply(n):
    num=len(str(abs(n)))
    return n*5**num

def multiply(n):
    e = len(str(abs(n)))
    return n * 5**e

def multiply(n):
    power = len(str(n)) if n >= 0 else len(str(n)) -1
    return n * 5 ** power

def multiply(n):
    return n*5**(len(str(n))) if "-" not in str(n) else n*5**(len(str(n))-1)

def multiply(n):
  return int(n)*5**len(str(abs(n)))

def multiply(n):
    
     lenght_of_n = len([i for i in str(n) if i.isdigit()])
     return n * 5 ** lenght_of_n 

def multiply(n):
    return n * 5**len(str(abs(n))) if n > 0 else n * 5**len(str(abs(n)))

def multiply(n):
    #your code here
    num = len(str(n))
    if n < 0:
        num -=1
    return n * 5 ** num

def multiply(n):
    if n >= 0:
        return n * (5 ** len(str(n)))
    else:
        return n * (5 ** len(str(n).replace('-','')))

import math
def multiply(n):
    sum=n*5
    digits = len(str(n))
    if n<0:
        digits=digits-1
    for x in range(digits-1):
        sum=(sum*5)
    return sum

def multiply(n):
  p = len(str(abs(n)))
  ans = n*(5**p)
  return ans

def multiply(n):
    if n >= 0:
        return n * (5 ** len(str(n)))
    if n < 0:
        return n * (5 ** (len(str(n))-1))
# Flez


def multiply(n):
    x = len(str(n).strip('-'))
    
    return n*5**x

def multiply(n):
    power = len(str(n))
    
    if n < 0:
        power -= 1
        
    return n * 5 ** power

def multiply(n):
    c = 0
    for i in str(n):
        for j in i:
            if j.isdigit():
                c += 1
    five = 1
    while c != 0:
        c -= 1
        five *= 5
    return five * n
    


def multiply(n):
    
    copy = str(n)
    length = len(copy)
    if n < 0:
        length = length - 1
    return n * (5**length)

def multiply(n):
    
    if n>=0:
        a=len(str(n))
        return n*(5**a)
    elif n<0:
        a = len(str(n))-1
        return n*(5**a)


def multiply(n):
    t,flag = (n,False) if n>0 else (abs(n),True)
    res = n*(5**len(str(t)))
    return res

import math

def multiply(n):
    if n == 0:
        digits = 1
    else:
        digits = int(math.log10(abs(n)))+1
    return n * 5 ** digits

def multiply(n):
    #your code here
    if n < 0:
        n = -n
        s = len(str(n))
        return 5 ** s * n * -1
    else:
        s = len(str(n))
        return 5 ** s * n


def multiply(n):
    count = 0
    if n < 0:
        num = -n
    else:
        num = n
    while num > 0:
        num = num // 10
        count += 1
    return (n*(5**count))

def multiply(n):
    if n < 0:
        return n *  (5 ** len(str(n*-1)))
        
    return n *  (5 ** len(str(n)))
    #your code here


def multiply(n):
    digits = len(str(abs(n)))
    return n*5**digits

def multiply(n):
    #your code here
    digits = len(list(str(n).lstrip('-')))
    return n * 5**digits

def multiply(n):
    a = len(str(n))
    if n >= 0:
        return n * 5 ** a
    return n * 5 ** (a -1)

def multiply(n):
    return n * 5 ** (lambda n: len(str(n)) if n >= 0 else len(str(n))-1)(n)

def multiply(n):
    if n>0: return n*(5**len(str(n)))
    else: return n*(5**(len(str(n))-1))

def get_digit_count(n):
    digits = 0
    while 0 < n:
        n //= 10
        digits += 1
    return digits

def multiply(n):
    return n * (5**get_digit_count(abs(n)))

def multiply(n):
    l = str(n)
    a = ""
    for c in l:
        if c in "0123456789":
            a += c
    
    return n * 5 ** len(a)

def multiply(n):
    s=len(str(abs(n)))
    p=5**s
    return n*p

def multiply(n):
    k = len(str(abs(n)))
    return n * 5 ** k

from math import fabs
def multiply(n):
    return n*(5**len(str(int(fabs(n)))))

def multiply(n):
    check = str(n)
    check = check.replace("-","")
    num = len(check)
    return 5 ** num * n

def multiply(n):
    l = len(str(n).replace("-",""))
    return n*5**l