Answer:
19938383
Step-by-step explanation:
Answer:

Step-by-step explanation:

72 and 45 can both be divided by 3.
So,
72 + 45
= 3 (24 + 15)
Answer:
The diameter by Pi or The radius multiplied by 2 time Pi
Step-by-step explanation:
This is because this is how you get the circumference.
Answer:
see below
Step-by-step explanation:
Closed under addition, subtraction and multiplication
Not closed under division :-
for example 3/4 = 0.75 which is not an integer