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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 959 · 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. 1.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  3. 3.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  5. 5.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  7. 7.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  10. 10.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  12. 12.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  14. 14.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  15. 15.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  17. 17.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  18. 18.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  20. 20.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  21. 21.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  23. 23.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  24. 24.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  30. 30.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  31. 31.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  33. 33.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  34. 34.A leapfrog list starts 5, 1 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): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  36. 36.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  37. 37.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  38. 38.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  39. 39.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  40. 40.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 374
  2. 671
  3. 1001
  4. 429
  5. 495
  6. 506
  7. 1199
  8. 374
  9. 572
  10. 451
  11. 1089
  12. 253
  13. 495
  14. 429
  15. 693
  16. 1034
  17. 946
  18. 539
  19. 308
  20. 781
  21. 605
  22. 891
  23. 759
  24. 781
  25. 759
  26. 1012
  27. 770
  28. 396
  29. 671
  30. 517
  31. 1034
  32. 528
  33. 913
  34. 363
  35. 605
  36. 737
  37. 143
  38. 1067
  39. 1056
  40. 1111

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