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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 15 · 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. 1.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  3. 3.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  4. 4.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  5. 5.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?
  6. 6.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.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?
  8. 8.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?
  9. 9.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  10. 10.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  13. 13.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?
  14. 14.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  15. 15.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  16. 16.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  17. 17.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  18. 18.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?
  19. 19.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.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?
  21. 21.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  23. 23.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  25. 25.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  26. 26.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  27. 27.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?
  28. 28.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  30. 30.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?
  31. 31.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  33. 33.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  35. 35.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  36. 36.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?
  37. 37.A leapfrog list starts 8, 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, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  39. 39.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  40. 40.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =

Answer key

  1. 847
  2. 759
  3. 484
  4. 715
  5. 1034
  6. 726
  7. 583
  8. 704
  9. 561
  10. 627
  11. 748
  12. 869
  13. 726
  14. 1034
  15. 1067
  16. 1177
  17. 968
  18. 1199
  19. 506
  20. 495
  21. 286
  22. 374
  23. 594
  24. 660
  25. 957
  26. 539
  27. 627
  28. 198
  29. 1056
  30. 528
  31. 1232
  32. 1232
  33. 517
  34. 583
  35. 781
  36. 715
  37. 792
  38. 462
  39. 517
  40. 363

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