Explanation:
Given : Empty Boxes with addition / subtraction and their ouput
To find : numbers in boxes full filling the given conditions
Solution:
Let assume left top corner number = a
now Right top corner would be = 16 - a
Left bottom corner would = 26 - a
Let assume bottom right corner = b
=> 16 - a + b = 16
=> b = a
also
26 - a - b = 12
=> a + b = 14
while a = b
=> 2a = 2b = 14
=> a = b = 8.0
16 - a = 8.0
13 - a = 20.0
8.0 + 8.0 = 16
+ +
20.0 - 8.0 = 12
↓ ↓
26 16