Answer: n = 3; n represents a remainder in a division problem.
Step-by-step explanation:
1) Finding n:
i) Given: 643 = 4 × 160 + n
ii) Do the operations: 643 = 640 + n
iii) Subraction property of the equality: 643 - 640 = n
iv) Do the operations: 3 = n
Answer: n 3
2) Meaning of n
When you divide 643 by 4 the quotient is 160 and the remainder is 3, because 160 × 4 = 640, and 643 - 640 = 3.
This is, 3 is what is left when you split 643 into 4 getting 160 whole parts (plus the remainder, 3).