import math
def roundDownToNearest500(num):
return math.floor(num / 500) * 500
print(roundDownToNearest500(3))
print(roundDownToNearest500(49))
print(roundDownToNearest500(550))
print(roundDownToNearest500(450))
print(roundDownToNearest500(500))
print(roundDownToNearest500(751))
print(roundDownToNearest500(1300))
print(roundDownToNearest500(-1))
print(roundDownToNearest500(-10))
print(roundDownToNearest500(-700))
'''
run:
0
0
500
0
500
500
1000
-500
-500
-1000
'''