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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 810 · 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 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  2. 2.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  3. 3.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?
  4. 4.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  5. 5.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  7. 7.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  8. 8.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  9. 9.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  10. 10.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  12. 12.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  15. 15.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?
  16. 16.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.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?
  19. 19.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?
  20. 20.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  21. 21.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?
  22. 22.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  23. 23.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  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. 25.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  26. 26.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  27. 27.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?
  28. 28.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  31. 31.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  37. 37.A leapfrog list starts 1, 6 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): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  39. 39.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?

Answer key

  1. 858
  2. 341
  3. 539
  4. 869
  5. 473
  6. 836
  7. 528
  8. 484
  9. 462
  10. 528
  11. 924
  12. 946
  13. 704
  14. 286
  15. 902
  16. 583
  17. 528
  18. 792
  19. 253
  20. 693
  21. 594
  22. 935
  23. 374
  24. 781
  25. 616
  26. 1001
  27. 539
  28. 1056
  29. 693
  30. 715
  31. 649
  32. 396
  33. 638
  34. 1089
  35. 649
  36. 1034
  37. 583
  38. 572
  39. 627
  40. 825

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