Target Range

Years 4 - 8

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Summary

This activity can be used with any of the four operations. Children choose a 'winning zone' or 'target range'. Player A makes the additional choice of the operation to use for this round. Then players take turns to operate on the calculator to be first to land in the range. Suitable for threading. 		 

Materials

  • One calculator between two

Note: This investigation has been included in Maths At Home. In this form it has fresh context and purpose and, in some cases, additional resources. Maths At Home activity plans encourage independent investigation through guided 'homework', or, for the teacher, can be an outline of a class investigation.
  • Visit the Home Page for more Background.
  • For this specific activity click the Learners link and on that page use Ctrl F (Cmd F on Mac) to search the task name.

Procedure

In this example Player A chooses to use multiplication as the challenge operation.
  1. Players agree on a Target Range, such as 370 to 390, and write it down.
  2. Players also agree on the operation for this round.
  3. Player A enters a start number, eg: 56.
    • All operations will now be 'times' for this round (if times is the one players have chosen).
  4. Player B guesses a number which he or she thinks will take the display into the Target Range and presses x, 'guess', =.
    • For example Player B might press, x 7, = because they know 7 x 50 = 350.
      The result will be 392.
  5. Player A then guesses the number which will take the 392 into the range and presses x, 'guess', =.
    • For example they might press x, 0·99, = and the result will be 388·08.
  6. In this case Player A wins because their action took the display into the agreed range.
Depending on the children's number sense skills, one round may take several attempts to reach the range. The winner scores one point and one game is best of five rounds (or other similar rule).

Variations

  1. The game works with any of the four operations and throws up interesting number sense challenges for each one. For example, when using addition and subtraction negative numbers can arise, and when using division, students may have to divide by a decimal to get a larger answer.
  2. Sometimes encourage children to record the sequence of calculations made to reach the Target Range and to review and comment on their guesses.
  3. What happens if the Target Range is between two non-whole numbers (perhaps 0·7 to 0·9)? ... or the multiplier is a decimal? ... or both?
  

Content

  • addition facts beyond 10
  • decimal calculations
  • decimal interpretation
  • decimal representation of a fraction
  • division
  • estimating number
  • exploring large numbers
  • fraction calculations
  • multiplication
  • negative numbers
  • operations - whole number
  • recording - calculator
  • subtraction
  • times tables


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Calculating Changes ... is a division of ... Mathematics Centre