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Which Would You Rather?

Age 7 to 11
Challenge Level Yellow star
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Marion at Tattingstone School and Aditya, who is from Bristol Grammar, both calculated these percentages carefully and came to sensible conclusions!

  1. Have 10% of £5 or 75% of 80p. 10% of £5 is 50p:
    10% of £5 = (10/100) * 500 = 5000/100 = 50
    and 75% of 80p is 60p. I'd rather have the latter.
  2. Have 60% of 2 pizzas or 26% of 5 pizzas. 60% of 2 is 1.2 and 26% of 5 is 1.3. Again, I'd rather have the latter.
  3. Get bitten by 15% of 120 mosquitoes or by 8% of 250 mosquitoes. 15% of 120 is 18 and 8% of 250 is 20. I'd prefer the first.
  4. Skip with a rope 54% of 105cm long or with one 88% of 2.75m long. 54% of 105cm is 56.7cm, and 88% of 2.75m is 2.42m = 242cm. I'd prefer using the longer rope.
  5. Get stuck in a traffic jam lasting 33% of 2 hours or 44% of 1 hr 40 mins. 33% of 120 minutes is 40 minutes, and 44% of 100 minutes is 44 minutes. I'd prefer neither!

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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.

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