how can we make 250 out of four numbers those numbers are 20,14,52,56...
The basic equation is,
250 = 320 - 70
and 70 = 14 + 56
and 320 = 4*80
and 4 = 56/14 and 80 = 4*20
Putting this all together,
250 = 320 - 70
250 = 4 * 80 - 70
250 = (56/14)*[(56/14)*20] - (14 + 56)
If we ignore the brackets and use operands (+, -, *, /) only,
250 = 56*56*20/14/14 - 14 - 56