Decimals With A Tape
Years 4 - 8

This investigation works best if you have a partner to talk with, so you need two of everything if possible.



  • Two [2] measuring tapes like the one shown,
    or cloth ones like those used in dressmaking.
  • At least one [1] calculator. (There's one on your phone.)
  • Print two copies of this Recording Sheet.
  • Write the title of this challenge and today's date on a fresh page in your maths journal.

Getting Started

  • Stretch out one tape across the table between you so that it reveals about 150cm.
    Put something on each end to stop it moving.
  • Start the activity by using the tape to help you fill in the answers on the
    Recording Sheet.
  • When you finish stick the sheet in your journal.

Have fun exploring Decimals With A Tape.


  • Open this Decimals With A Tape starter. You can read it on screen or print it.
  • Your challenge is to work together to discover how to add, subtract, multiply and divide decimals.
    Experiment with the tapes, talk, explain, test.
    You don't have to discover everything today.
    Keep coming back to learn more.
  • Remember to keep good notes and diagrams in your journal.

Just Before You Finish

  • Prove you have been working like a mathematician.
    • Open the link.
    • Read it through together.
    • In your journal make a list of all the things you did in this activity that are also things a mathematician does.
  • You worked like a mathematician with decimals so you could make rules to tell others how to work them out.
    • One of you make a wall poster to explain addition or subtraction.
    • The other one make a poster to explain multiplication or division.


Answers & Discussion

These notes were originally written for teachers. We have included them to support parents to help their child learn from Decimals With A Tape.


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Maths At Home is a division of Mathematics Centre