Maths Challenge – What are my 7 cards?

I have fifteen cards number from 1 to 15.

I put down 7 of them on the table in a row, like this:

The numbers on the first two cards add to 15.

The numbers on the second and third cards add to 20.

The numbers on the third and fourth cards add to 23.

The numbers on the fourth and fifth cards add to 16.

The numbers on the fifth and sixth cards add to 18.

The numbers on the sixth and seventh cards add to 21.

Hints and Tips

  1. Make a set of 15 number cards.
  2. Try out different combinations of cards.
  3. Focus on one pair of cards at a time.
  4. Don’t forget – 12 followed by 3 will give a different order to 3 followed by 12.
  5. Look for pairs of cards that can’t work for each total.

18 thoughts on “Maths Challenge – What are my 7 cards?

  • 20th March 2020 at 8:30 pm
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    Hey. Freya here, hope you are all OK. I have the answer for bronze!!! I think that it is 4,11,9,14,2,16,5. I hope its correct!!😃😃

    Reply
  • 20th March 2020 at 8:34 pm
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    Card 1 is 1
    Card 2 is 14
    Card 3 is 6
    Card 4 is 9
    Card 5 is 7
    Card 6 is 11
    Card 7 is 10

    Reply
    • 23rd March 2020 at 9:55 am
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      Great effort Edward. There is one pair of cards where it doesn’t work. Can you spot them?

      Reply
      • 23rd March 2020 at 10:51 am
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        I have spotted them it’s the 3 and 4th card here is my changed answers of 3 and 4
        Card 3 is 14
        Card 4 is 9

        Reply
        • 23rd March 2020 at 11:15 am
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          Ok. So what are the 7 cards that you have ended up with?

          Reply
          • 24th March 2020 at 3:22 pm
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            Card 1 is 1
            Card 2 is 14
            Card 3 is 13
            Card 4 is 10
            Card 5 is 6
            Card 6 is 12
            Card 7 is 9

        • 23rd March 2020 at 4:39 pm
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          6+9=15 9+11=20 11+12=23 12+4=16 4+14=18 14+7=21

          Reply
  • 23rd March 2020 at 9:58 am
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    Well done Freya for achieving the bronze level!

    Reply
  • 23rd March 2020 at 11:35 am
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    bronze: 6,9,11,12,4,14,7 silver: I couldn’t find any more
    gold: when I get on the 4th/5th, it doesn’t work . only one way works
    platinum: cards 15 to 30 . 8 cards have been layed out cards 1,2,3 should be 72
    cards 3,4 should be 41 . cards 4,5,6 should be 58. cards 6,7,8 should be 71

    Reply
  • 23rd March 2020 at 11:42 am
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    Card 1 is 6
    card 2 is 9
    card 3 is 11
    card 4 is 12
    card 5 is 4
    card 6 is 14
    card 7 is 7

    Reply
  • 23rd March 2020 at 1:42 pm
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    Well done Zofia and Skye for completing the bronze challenge.

    Skye – I think there might be another solution as someone else in Year 6 has found one which is different to yours. Keep looking!

    Reply
  • 23rd March 2020 at 4:51 pm
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    The cards are:
    8,7,13,10,6,12,9
    Also:
    6,9,11,12,4,14,7

    Reply
  • 23rd March 2020 at 6:19 pm
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    6,9,11,12,4,14,7

    Reply
  • 24th March 2020 at 9:42 am
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    The first cards I got were:
    8,7,13,10,6,12,9

    My other solution was:
    6,9,11,12,4,14,7

    Reply
  • 24th March 2020 at 12:34 pm
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    1.10 1.13
    2.5 2.2
    3.15 3.18
    4.7 4.5
    5.9 5.11
    6.9 6.7
    7.12 7.14

    Reply
  • 24th March 2020 at 2:26 pm
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    hi its me Amelie I have an answer for bronze 5,10,10,13,3,15,6

    Reply
  • 25th March 2020 at 8:17 am
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    Bronze.
    Card 1=6 Card 2=9 Card 3=11 Card 4=12 Card 5=4 Card 6=14 Card 7=7

    Reply
  • 27th March 2020 at 3:57 pm
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    The cards are
    10, 5 ,15, 8 ,8 ,10 ,11

    Reply

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