If you don’t have rounding function available like in older versions of ruby, you can do rounding by using floor and modulo functions

Trough floor ( takes only integer part) function it could be done so :

if (shm - (floor(shm/100 000)*100000)) >= 50000 ; then
   shmall= ((floor(shm/100 000)+1)*100 000)
else
   shmall=(floor(shm/100 000)*100 000)
fi

Trough modulo (gives reminder of division):

if mod(shm/100 000) > 50000 ; then
   shmall= shm+ (100 000-mod(shm/100 000))
else
   shmall= shm- mod(shm/100 000)
fi

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