Calculate the concentration of a dilute acid given the amount and concentration of dilute alkali to neutralise it. Cribbed from this Bitesize problem.

There are steps to break down the calculation, and the student must give units at each step.

Preparing solutions to given concentrations/dilutions.

This question is made up of 10 exercises to practice the expansion of brackets.

Given a generator matrix for a linear code, write a parity check matrix, compute the syndrome of a word, and decide if it's a codeword.

Expression of the (a+bx)^n is given and a couple of coefficients are asked for.

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Use the testing tab in the variables section to make sure the generated variables satisfy a condition

This question loads an extension which contains a dataset in JSON format. The data is made available as a JME variable called 'animal_data'.

Given percentages of males and females working on a project, and the percentage of the total staff who are male (or female), find the percentage of all staff working on the project.

Based on question 3 from section 3 of the maths-aid workbook on numerical reasoning.

A quick implementation of certainty-based marking: the student's score depends on how they rated their certainty in their answer before submission.

Because Numbas doesn't allow negative marking at the moment, scores are shifted upwards, so a high certainty incorrect answer scores 0, and a high certainty correct answer scores full credit.

4 questions on using partial fractions to solve indefinite integrals.

Adapted from section 7.3.1 in OpenIntro Statistics (4th ed).

Addition and subtraction of matrices; multiplication by scalar.

A really simple question which asks the student to multiply two matrices.

JSXGraph code based on original by Christian Lawson-Perfect

Choose from one of several pre-defined scenarios, and set variables to the corresponding values. 

This question has three variables: city, population, and percent_like_chocolate. These differ for each city. 

A collection of questions to show off at a workshop for the North East and Yorkshire sigma hub, June 2016.

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Some questions to show off features of Numbas, linked from the Numbas homepage.

Three equilateral triangles are divided equally into 3, 4 and 5 parts respectively. Calculate the distance between two marked points.

Based on a puzzle by Catriona Shearer, shared on Twitter.

A collection of questions to show off at a workshop for Newcastle's LTDS, June 2016.