Fun with Mathematics

Magic Number
Take any three digit number
Write the number in generalized form.
as         100a+10b+c    
write    100c+10a+b
write    100b+10c+a
Add them
The sum will be divisible by 37.Why?

Example:

237               2X100+3X10+7 =   237
                     7X100+2X10+3 =   723
                     3X100+7X10+2=    372

sum =                                           1332   is divisible by 37

Can you explain Why?