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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 726 · 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.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  3. 3.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  4. 4.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?
  5. 5.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  7. 7.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?
  8. 8.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  9. 9.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  10. 10.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  11. 11.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  12. 12.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?
  13. 13.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  14. 14.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?
  15. 15.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?
  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.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  19. 19.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  20. 20.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?
  21. 21.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  24. 24.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?
  25. 25.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  26. 26.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  27. 27.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?
  28. 28.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  29. 29.A leapfrog list starts 1, 4 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): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  31. 31.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?
  32. 32.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  34. 34.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  37. 37.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?
  38. 38.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  39. 39.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  40. 40.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 561
  2. 1089
  3. 748
  4. 528
  5. 715
  6. 616
  7. 627
  8. 693
  9. 649
  10. 506
  11. 583
  12. 396
  13. 418
  14. 506
  15. 869
  16. 231
  17. 1232
  18. 605
  19. 286
  20. 902
  21. 341
  22. 517
  23. 583
  24. 583
  25. 451
  26. 803
  27. 143
  28. 231
  29. 407
  30. 1232
  31. 605
  32. 363
  33. 198
  34. 935
  35. 473
  36. 616
  37. 1001
  38. 1012
  39. 495
  40. 319

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