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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 151 · 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.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?
  2. 2.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  3. 3.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?
  4. 4.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?
  5. 5.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  6. 6.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  7. 7.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?
  8. 8.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  9. 9.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  10. 10.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?
  11. 11.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  12. 12.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  13. 13.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  14. 14.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?
  15. 15.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  17. 17.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  18. 18.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  19. 19.A leapfrog list starts 6, 4 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 2, 6 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 6, 6 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 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  24. 24.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?
  25. 25.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  26. 26.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?
  27. 27.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  28. 28.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?
  29. 29.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?
  30. 30.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?
  31. 31.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  32. 32.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  34. 34.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?
  35. 35.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.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?
  37. 37.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 583
  2. 506
  3. 484
  4. 506
  5. 495
  6. 957
  7. 374
  8. 1001
  9. 484
  10. 1034
  11. 1287
  12. 319
  13. 1232
  14. 902
  15. 1023
  16. 341
  17. 1012
  18. 770
  19. 682
  20. 638
  21. 858
  22. 451
  23. 847
  24. 198
  25. 374
  26. 231
  27. 1067
  28. 1001
  29. 396
  30. 693
  31. 594
  32. 847
  33. 902
  34. 539
  35. 1067
  36. 627
  37. 429
  38. 869
  39. 363
  40. 495

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