Find sum of all the numbers that are multiples of 10 and are less than or equal to a given number "N". (quotes for clarity and be careful of integer overflow)

-----Input-----
Input will start with an integer T the count of test cases, each case will have an integer N.

-----Output-----
Output each values, on a newline.

-----Constraints-----
- 1 ≤ T ≤ 10
- 1 ≤ N ≤1000000000

-----Example-----
Input:
1
10

Output:
10

-----Explanation-----
Example case 1. Only integer that is multiple 10 that is less than or equal to 10 is 10

Difficulty: interview

Starter code:

Solutions:
for t in range(eval(input())):
 n=eval(input())
 n-=n%10
 n/=10
 print(n*(n+1)/2*10)

def tenn():
 t=eval(input())
 for i in range(t):
  a=eval(input())
  r=a/10
  t=(r*(r+1))/2
  print(t*10)
tenn()


t = int(input())
l = list()

for i in range(t):
 n = int(input()) / 10
 l.append(n)
 
for n in l:
 print(int(n * (n + 1) / 2.0 * 10))



def main():
 t=int(input())
 while(t!=0):
  t=t-1
  N=int(input())
  print(5*int(N/10)*(int(N/10)+1))
 return(0)

main()

t=int(input())
while t:
 n=int(input())
 t-=1
 r=n/10
 r=10*(r*(r+1))/2
 print(r)