Example: Find the range of the following: 1, 2, 4, 5, 5
Step 1: Sort the list → 1, 2, 4, 5, 5
Step 2: Highest number → 5; Lowest number → 1
Step 3: Difference between the highest and the lowest numbers in the list → 5 - 1 = 4. Therefore, the range is 4.

Example: 1, __ , 3, 4, 5; mean=3
Step 1: Let N be the missing number.
Step 2: We know, Mean = (Sum of all numbers)/(Number of numbers);
Therefore, Sum of all numbers = Mean x Number of numbers
→ 1 + N + 3 + 4 + 5 = 3 x 5 → N + 13 = 15 → N = 15-13 → N = 2

Example: What is the coefficient of 2y?
Answer: 2
Note: Numerical coefficient is the numeral part in a term.

Example: Find the median of the following: 1, 2, 1, 5, 5
Step 1: Sort the list → 1, 1, 2, 5, 5
Step 2: Count of numbers listed → 5 (odd)
Step 3: So the middle number is (count+1)/2 → (5+1)/2 → 3^rd number. Therefore, the median is 2.