11+ Maths

Algebra in the 11+ — Questions, Worked Answers and Practice Papers

Using letters for unknowns — forming expressions, solving equations and applying algebra in 11+ word problems.

130 Papers
5.1 Avg Qs / paper
2.12 Typical marks
1.1 min Target time

What examiners actually ask

Algebra appears in 130 of our 338 ready papers (658 tagged questions). It averages 5.1 questions a paper worth about 2.12 marks each. The typical question allows around 1.1 min. It appears in 2 CSSE papers we hold.

Algebra in the 11+ is rarely abstract for its own sake. Papers ask children to form an expression from a sentence, solve a one- or two-step equation, or find an unknown on a diagram. Independent schools push this harder; grammar-style papers often hide algebra inside word problems. The children who struggle usually understand “find x” in a neat equation but freeze when the unknown is described in words. Good practice pairs clean equation drills with “write an expression for…” questions so the method transfers under time pressure. Teach them to underline the unknown, translate each phrase into symbols, then balance both sides carefully. A quick substitution check at the end catches most arithmetic slips before they cost the mark.

Worked example

A real tagged question from our catalogue — method included, not paywalled.

Manchester Grammar School 11+ Maths 2010 Paper 2 · Question 12 · 5 marks · Algebra

Correct answer
{"object":"table","data":[["Position","Country","Gold","Silver","Bronze","Total"],["1st","A","9","8","2","19"],["2nd","B","7","4","7","18"],["3rd","C","6","7","4","17"],["4th","D","2","4","8","14"],["5th","E","2","3","5","10"],["","","26","26","26","78"]]}
Method
The approach to this question is to first target the low hanging fruit. In other words, let's find the ones that are easy to calculate or require less calculation.  Let's start with country E, as this is the most straightforward. The medals are in the order of prime numbers. The first three prime numbers are 2, 3 and 5. So the medals for E are, Gold = 2, Silver = 3 and Bronze = 5 Total medals = 2 + 3 + 5 = 10 (Remember 1 is not a prime number because it only has one factor. Prime numbers have exactly two factors.) There are 26 events that mean there are 26 gold, 26 silver and 26 bronze medals to be won. The total number of medals to be won in the whole event are = 26 + 26 + 26  Total of all medals = 78 Next, let's focus on C as we have a lot more information about C than others.  C has won a total of 17 medals out of which 4 are bronze. This means that the remaining 13 are gold and silver.  As per the question, if C won x gold medals then their silver medals are (x+1). We also know that, gold + silver = 13 We can put this information in an equation. So, x + (x + 1) = 13 2x + 1 = 13 2x = 13 - 1 2x = 12 x = 12/2 = 6 This means that there are 6 gold and 7 silver. Next, let's look at D. Because we know that the teams are arranged in the order of medals won and we know that the total of C is 17 and E is 10. The total medals of D must be some number between 10 and 17. It can be 11, 12, 13, 14, 15 or 16. Which we need to figure out. As per the question, if the number of gold medals won by D is x. Then, silver = 2 times gold and bronze = 2 times silver. Silver = 2x and Bronze = 4x. The total medals won by D are then, x + 2x + 4x = 7x 7x must be equal to 11, 12, 13, 14, 15 or 16. So now let's understand how do we narrow it down to one of those numbers.  If 7x = 11, then x = 11/7.  We cannot divide 11 into 7 equal parts so this cannot be the answer. In a similar, way the only number in the list that is divisible by 7 is 14. If 7x = 14, then x = 14/7.  Then x = 2.  Gold = 2, Silver = 4 and Bronze = 8 The total of gold medals across all 26 events is 26. Out of which B has 7, C has 6, D has 2 and E has 2. So gold for A can be calculated with the data we have. A = 26 - (7 + 6 + 2 + 2) A = 26 - 17 A = 9 The total of bronze medals across all 26 events is 26. Out of which A has 2, C has 4, D has 8 and E has 5. So bronze for B can be calculated with the data we have. B = 26 - (2 + 4 + 8 + 5) B = 26 - 19 B = 7 The question does not give us any other clues about A and B. So we need to think out of the box.  We know that the total medals are 78.  We also know now that total of C is 17, D is 14 and E is 10 Total of C,D and E are  = 17 + 14 + 10 = 41 This means that the remaining medals, that A and B have are 78 - 41 = 37 Remember that the countries are arranged in the order of position. That means that B must have more medals than C. If we assume that B has 18, then the number of medals left for A must be more than 18 for A to be in the first position.  Let's put that in an equation and see what we get.  A = total left - B A = 37 - 18 A = 19. This looks good so far but let's perform one more test.  If we assume that B has 19. Then A = 37 - 19 = 18 This cannot be true because being in the first position must have more than B.  So the only possibility is that A has 19 and B has 18. Now calculate the silver medals for A. Silver = total - (gold + bronze) Silver = 19 - (9 + 2) Silver = 19 - 11 = 8 Now calculate the silver medals for B. Silver = total - (gold + bronze) Silver = 18 - (7 + 7) Silver = 18 - 14 = 4 Finally we have,  A = 9G + 8S + 2B = 19 B = 7G + 4S + 7B = 18 C = 6G + 7S + 4B = 17 D = 2G + 4S + 8B = 14 E = 2G + 3S + 5B = 10

Common mistakes

  • Writing the expression in the wrong order from a worded sentence (e.g. “3 less than n” as 3 − n).
  • Doing the same operation to only one side of an equation.
  • Forgetting to check the solution in the original equation when marks are tight.
  • Treating algebra as “guess and check” instead of balancing both sides.

Papers with the most Algebra questions

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