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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 384 · 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. 1.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  3. 3.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?
  4. 4.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  6. 6.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?
  7. 7.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  8. 8.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?
  9. 9.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  10. 10.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  12. 12.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?
  13. 13.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  14. 14.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  15. 15.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  16. 16.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?
  17. 17.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  18. 18.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?
  19. 19.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.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?
  21. 21.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  22. 22.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  24. 24.A leapfrog list starts 7, 5 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 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.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?
  27. 27.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  28. 28.A leapfrog list starts 1, 7 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): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  30. 30.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.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?
  32. 32.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  34. 34.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  35. 35.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  36. 36.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  37. 37.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?
  38. 38.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  39. 39.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  40. 40.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?

Answer key

  1. 880
  2. 803
  3. 1199
  4. 253
  5. 143
  6. 319
  7. 935
  8. 946
  9. 693
  10. 638
  11. 1111
  12. 319
  13. 715
  14. 1177
  15. 825
  16. 627
  17. 253
  18. 429
  19. 847
  20. 539
  21. 1122
  22. 671
  23. 638
  24. 825
  25. 396
  26. 781
  27. 946
  28. 671
  29. 693
  30. 924
  31. 506
  32. 1001
  33. 594
  34. 429
  35. 770
  36. 462
  37. 1089
  38. 968
  39. 308
  40. 638

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