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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 50 · 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. 1.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  2. 2.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  5. 5.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  6. 6.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  7. 7.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?
  8. 8.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.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?
  10. 10.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  12. 12.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  13. 13.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  15. 15.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?
  16. 16.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  18. 18.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.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?
  20. 20.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?
  21. 21.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  22. 22.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  23. 23.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  24. 24.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  25. 25.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  26. 26.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  27. 27.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  29. 29.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  30. 30.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  35. 35.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  36. 36.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  38. 38.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  39. 39.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?
  40. 40.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =

Answer key

  1. 396
  2. 1034
  3. 880
  4. 836
  5. 847
  6. 1012
  7. 1111
  8. 605
  9. 451
  10. 836
  11. 484
  12. 792
  13. 726
  14. 1111
  15. 539
  16. 781
  17. 638
  18. 902
  19. 1122
  20. 671
  21. 231
  22. 638
  23. 968
  24. 715
  25. 363
  26. 1089
  27. 407
  28. 649
  29. 341
  30. 891
  31. 869
  32. 1122
  33. 1144
  34. 902
  35. 583
  36. 616
  37. 539
  38. 1001
  39. 726
  40. 869

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