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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 669 · 40 questions
TalentJR

The trick (Seventh times eleven): A leapfrog list: start with two numbers, then each number is the sum of the two before it, up to 10 numbers. Find the 7th number. Multiply it by 11 (the number with a 0 on the end, plus the number): that is the total of all 10.

NameDateTime takenScore ___ / 40
  1. 1.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  3. 3.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  5. 5.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  6. 6.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  8. 8.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  9. 9.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  10. 10.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  12. 12.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  14. 14.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  15. 15.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  17. 17.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  18. 18.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  21. 21.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  23. 23.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  25. 25.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  27. 27.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  28. 28.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  29. 29.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  31. 31.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  32. 32.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  33. 33.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  34. 34.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  36. 36.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  39. 39.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  40. 40.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 418
  2. 627
  3. 649
  4. 253
  5. 616
  6. 737
  7. 979
  8. 836
  9. 1111
  10. 726
  11. 1067
  12. 616
  13. 231
  14. 968
  15. 693
  16. 231
  17. 473
  18. 594
  19. 1067
  20. 528
  21. 803
  22. 671
  23. 253
  24. 759
  25. 847
  26. 1089
  27. 594
  28. 957
  29. 1177
  30. 605
  31. 1122
  32. 286
  33. 341
  34. 880
  35. 1023
  36. 814
  37. 572
  38. 726
  39. 902
  40. 550

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