Skip over navigation
Cambridge University Faculty of Mathematics NRich logo
menu search
  • Teachers expand_more
    • Early years
    • Primary
    • Secondary
    • Post-16
    • Events
    • Professional development
  • Students expand_more
    • Primary
    • Secondary
    • Post-16
  • Parents expand_more
    • Early Years
    • Primary
    • Secondary
    • Post-16
  • Problem-Solving Schools
  • About NRICH expand_more
    • About us
    • Impact stories
    • Support us
    • Our funders
    • Contact us
  • search

Or search by topic

Number and algebra

  • The Number System and Place Value
  • Calculations and Numerical Methods
  • Fractions, Decimals, Percentages, Ratio and Proportion
  • Properties of Numbers
  • Patterns, Sequences and Structure
  • Algebraic expressions, equations and formulae
  • Coordinates, Functions and Graphs

Geometry and measure

  • Angles, Polygons, and Geometrical Proof
  • 3D Geometry, Shape and Space
  • Measuring and calculating with units
  • Transformations and constructions
  • Pythagoras and Trigonometry
  • Vectors and Matrices

Probability and statistics

  • Handling, Processing and Representing Data
  • Probability

Working mathematically

  • Thinking mathematically
  • Developing positive attitudes
  • Cross-curricular contexts

Advanced mathematics

  • Decision Mathematics and Combinatorics
  • Advanced Probability and Statistics
  • Mechanics
  • Calculus

For younger learners

  • Early Years Foundation Stage

Pies

Age 7 to 11
Challenge Level Yellow starYellow star
  • Problem
  • Getting Started
  • Student Solutions
  • Teachers' Resources

Matthew and James recorded their answer as a fraction, 433 $\frac{1}{3}$ grams. Helena of Bebington and Christina, of Malborough Primary School, recorded their answers as decimal fractions. But each of these people used a combination of fractions and decimals to arrive at their solutions.

Can you follow their thinking as they calculated the answer?

Matthew explained the procedure he used:

I got my answer of 433 $\frac{1}{3}$ grams by putting the problem into an equation. These are the steps I took to get the answer:

  1. First I did the sum $200$g. + $125$g. which equalled $325$g.
  2. Then I wrote it down like this: $325$g. + $\frac{1}{4}$ pie = pie
    I then converted this to: $325$g. +$\frac{1}{4}$ pie = $\frac{4}{4}$ pie (or one whole pie).
  3. Next, I took $\frac{1}{4}$ of a pie from each side leaving me with: $325$g. = $\frac{3}{4}$ pie.
  4. I multiplied each side by $4$ which came out as: $1300$ = $3$ pies

    But Matthew only wanted to find the weight of one pie, so he did this last important step:

  5. I divided each side by $3$ and came to the final answer of:433 $\frac{1}{3}$ grams = $1$ pie."

Helena described her method this way:

$\frac{1}{4}$ pie = $325$g. divided by $3$, which is $108.3$g.
So, $4 \times \frac{1}{4}$ of a pie = $4 \times108.3$g. or $433.2$g.
$433.2$ grams is weight of a whole pie"


You may also like

Pizza Portions

My friends and I love pizza. Can you help us share these pizzas equally?

Doughnut

How can you cut a doughnut into 8 equal pieces with only three cuts of a knife?

Red Balloons, Blue Balloons

Katie and Will have some balloons. Will's balloon burst at exactly the same size as Katie's at the beginning of a puff. How many puffs had Will done before his balloon burst?

  • Tech help
  • Accessibility Statement
  • Sign up to our newsletter
  • Twitter X logo

The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.

NRICH is part of the family of activities in the Millennium Mathematics Project.

University of Cambridge logo NRICH logo