def checkSum(a, b):
    result1 = a + b
    return result1


def checksub(c, d):
    result2 = c - d
    return result2


num1 = 20
num2 = 30
print("sum=", checkSum(num1, num2))
num3 = 10000
num4 = 5000
print("sub=", checksub(num3, num4))
