Expressions with 1 variable worksheets | Worsheets library - Free Printable

Let's solve the algebraic expressions step by step based on the worksheet you provided.

---

Part A: Evaluate each expression when $ x = 9 $

We substitute $ x = 9 $ into each expression:

1) $ x + 12 = 9 + 12 = \boxed{21} $

2) $ 8 + x = 8 + 9 = \boxed{17} $

3) $ 20 + x = 20 + 9 = \boxed{29} $

4) $ 4 + x = 4 + 9 = \boxed{13} $

5) $ x + 14 - 15 = 9 + 14 - 15 = 23 - 15 = \boxed{8} $

6) $ x - 3 = 9 - 3 = \boxed{6} $

7) $ 1 + x = 1 + 9 = \boxed{10} $

8) $ x - 1 = 9 - 1 = \boxed{8} $

9) $ x + 11 = 9 + 11 = \boxed{20} $

10) $ x + 6 = 9 + 6 = \boxed{15} $

---

Part B: Evaluate each expression when $ y = 5 $

Now we substitute $ y = 5 $ into each expression:

11) $ y + 17 = 5 + 17 = \boxed{22} $

12) $ y + 18 = 5 + 18 = \boxed{23} $

13) $ y - 5 = 5 - 5 = \boxed{0} $

14) $ 12 + y = 12 + 5 = \boxed{17} $

15) $ y + 14 - 13 = 5 + 14 - 13 = 19 - 13 = \boxed{6} $

16) $ 11 - y = 11 - 5 = \boxed{6} $

17) $ y - 2 = 5 - 2 = \boxed{3} $

18) $ 9 + y = 9 + 5 = \boxed{14} $

19) $ y + 7 = 5 + 7 = \boxed{12} $

20) $ y + 15 - 5 = 5 + 15 - 5 = 20 - 5 = \boxed{15} $

---

✔ Final Answers:

Part A (x = 9):
1) 21
2) 17
3) 29
4) 13
5) 8
6) 6
7) 10
8) 8
9) 20
10) 15

Part B (y = 5):
11) 22
12) 23
13) 0
14) 17
15) 6
16) 6
17) 3
18) 14
19) 12
20) 15

---

🔍 Explanation:

- This is a substitution exercise in algebra.
- We replace the variable ($ x $ or $ y $) with its given value.
- Then, perform arithmetic operations as usual (addition, subtraction).
- Order of operations applies — but since most are simple additions/subtractions, we just go left to right.

This helps build foundational skills for solving more complex equations later. Let me know if you'd like a printable version or further explanation!