When you need to check multiple conditions, use elif (short for "else if"):
Python checks each condition from top to bottom. The first one that's True gets executed, and the rest are skipped.
Relational operators compare two values:
score = 85
if score >= 90:
print('A')
elif score >= 80:
print('B')
elif score >= 70:
print('C')
elif score >= 60:
print('D')
else:
print('F')