11+ Algebra & Equations
Master balancing linear equations, two-way function machines, substitution and symbol puzzles with visual step-by-step methods.
Algebra frequently separates top scorers in grammar school entrance exams (GL & CEM). Mastering inverse operations and symbol replacement guarantees quick, confident marks.
11+ Algebra & Equation Explorer
Interactive Tool11+ Algebra Methods & Exam Traps
Master these proven methods and avoid the standard pitfalls that trip up candidates in GL Assessment and CEM papers.
The 4 Core 11+ Algebra Methods
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.When given the final output of a multi-stage machine, write out the operations in reverse order, inverting each arithmetic sign as you go.
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!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 + 1.11+ Common Algebra Traps & Fixes
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.When solving
3x + 5 = 26, do not divide by 3 first! Always peel off additions/subtractions before division/multiplication.In
4a, if a = 5, the answer is 4 × 5 = 20, never 45!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).11+ Algebra & Numbers Practice Test
Test your understanding with authentic 11+ multiple-choice exam questions covering linear equations, function machine inverses, and number series.
11+ General Maths & Algebra Worksheet
Printable PDF worksheet with balanced equation challenges, function tables, and detailed answer sheet.
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