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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 634 · 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): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  3. 3.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  4. 4.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  5. 5.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  7. 7.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  8. 8.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  9. 9.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?
  10. 10.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  12. 12.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  13. 13.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?
  14. 14.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?
  15. 15.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?
  16. 16.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?
  17. 17.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  18. 18.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  19. 19.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?
  20. 20.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  21. 21.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?
  22. 22.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  23. 23.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  24. 24.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?
  25. 25.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?
  26. 26.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  27. 27.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  28. 28.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  31. 31.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  32. 32.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  33. 33.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?
  34. 34.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  35. 35.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?
  36. 36.A leapfrog list starts 4, 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 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  40. 40.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 462
  2. 550
  3. 649
  4. 814
  5. 693
  6. 979
  7. 495
  8. 539
  9. 1122
  10. 1199
  11. 682
  12. 286
  13. 1232
  14. 374
  15. 726
  16. 528
  17. 572
  18. 759
  19. 539
  20. 682
  21. 583
  22. 913
  23. 1034
  24. 429
  25. 528
  26. 319
  27. 143
  28. 429
  29. 484
  30. 759
  31. 583
  32. 561
  33. 473
  34. 528
  35. 1001
  36. 572
  37. 814
  38. 649
  39. 1001
  40. 836

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