11+ Maths Curriculum Ages 9–11 GL & CEM Assessment

11+ Algebra & Equations

Master balancing linear equations, two-way function machines, substitution and symbol puzzles with visual step-by-step methods.

Interactive Balance Scale Lab Function Machine Pipeline Symbol & Fruit Puzzles nth Term Sequence Rule 11+ Speed Drill
11+ EXAM WEIGHTING
Core Topic: 3–5 Marks

Algebra frequently separates top scorers in grammar school entrance exams (GL & CEM). Mastering inverse operations and symbol replacement guarantees quick, confident marks.

✓ Balance Scale Inverse Method
✓ Working Backwards from Output
✓ Symbol Elimination Puzzles

11+ Algebra & Equation Explorer

Interactive Tool
Hands-on practice with dynamic sliders & physics feedback
💡 Golden Rule of Algebra: An equation is like a balance scale. Always do the exact same inverse operation to both sides to isolate x!
Core 11+ Method Solve Equations with Balance Physics
Rule: Keep the scale level by applying the same inverse operation to both pans.
LEFT PAN: Variable & Constants
⚖️ Adjust x to balance
RIGHT PAN: Target Weight
Left Weight: 0
Right Weight: 0
EQUATION: 2x + 6 = 18
Coefficient of x (piles) 2
Constant added/subtracted +6
Target Right Pan Total 18
🎯 Student Guess for x x = ?
Adjust the slider to balance the scale or use the Step buttons!
11+ EXAM PRESETS:
Two-Step Machine Function Machines & Inverse Arithmetic
Input (n)
6
Starting Value
➔
⚙️
Operation 1
× 3
Mid: 18
➔
⚙️
Operation 2
+ 5
Final step
➔
Output
23
Result
Input Value (n) 6
Operation 1
Operation 2
🔄 Working Backwards (Exam Technique):
To find the starting input from an output of 23: reverse Op 2 (23 - 5 = 18), then reverse Op 1 (18 ÷ 3 = 6).
11+ FUNCTION CHALLENGES:
11+ Favourite Simultaneous Symbol & Fruit Equations
Method: Compare equations to eliminate one variable immediately.
GIVEN PROBLEM:
🍎 + 🍎 + 🍌
=
22
🍎 + 🍌
=
15
11+ EXAM PUZZLES:
Pattern Master Sequences & Deriving the nth Term
Shortcut: nth Term = (Difference × n) + (Zero-th Term)
SEQUENCE TERMS: Difference: +3
General Rule (nth Term Formula)
3n + 1
Multiplier = 3 (the jump). Zero term = 4 - 3 = +1.
Calculate Term at n = 20
61
3(20) + 1 = 61
First Term (a) 4
Common Difference (d) +3
Find Nth Term at n = 20
11+ EXAM SEQUENCES:
Live Practice 11+ Algebra Speed Drill
Streak: 0 Score: 0 / 0
LINEAR EQUATION
Solve for x: 3x + 7 = 28

11+ Algebra Methods & Exam Traps

Master these proven methods and avoid the standard pitfalls that trip up candidates in GL Assessment and CEM papers.

1

The 4 Core 11+ Algebra Methods

1. The Balance Scale Method (Inverse Operations):
Whatever operation is attached to the variable, undo it with the opposite operation on both sides:
• Undo addition with subtraction (+5 → −5)
• Undo multiplication with division (×3 → ÷3)
Example: 4x + 7 = 31 ⇒ 4x = 24 ⇒ x = 6.
2. Reversing Function Machines (Working Backwards):
When given the final output of a multi-stage machine, write out the operations in reverse order, inverting each arithmetic sign as you go.
3. Symbol Elimination & Substitution:
When two equations feature icons or objects (e.g. 2 Apples + 1 Banana = 22; 1 Apple + 1 Banana = 15), subtract Equation 2 from Equation 1 to find the value of 1 Apple instantly (22 − 15 = 7). Then substitute back!
4. The nth Term Sequence Rule:
For any linear sequence (e.g. 4, 7, 10, 13…):
1. Find the step difference: +3 ⇒ 3n.
2. Subtract difference from 1st term to find the zero-term adjustment: 4 − 3 = +1.
3. Formula: 3n + 1.
2

11+ Common Algebra Traps & Fixes

⚠️ Trap 1: The Minus-Before-x Sign Error:
In 15 − 2x = 7, students often write 2x = 15 + 7 = 22.
Fix: Add 2x to both sides first: 15 = 7 + 2x ⇒ 8 = 2x ⇒ x = 4.
⚠️ Trap 2: Reversing Order of Operations:
When solving 3x + 5 = 26, do not divide by 3 first! Always peel off additions/subtractions before division/multiplication.
⚠️ Trap 3: The Multiplied Letter Confusion:
In 4a, if a = 5, the answer is 4 × 5 = 20, never 45!
⚠️ Trap 4: Bracket Distributive Oversight:
In 3(x + 4) = 27, remember that 3 multiplies both terms inside (3x + 12 = 27), OR divide both sides by 3 immediately (x + 4 = 9 ⇒ x = 5).
PRACTICE ARENA

11+ Algebra & Numbers Practice Test

Test your understanding with authentic 11+ multiple-choice exam questions covering linear equations, function machine inverses, and number series.

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11+ General Maths & Algebra Worksheet

Printable PDF worksheet with balanced equation challenges, function tables, and detailed answer sheet.

Download PDF Worksheet ➔

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