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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 103 · 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): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  2. 2.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  3. 3.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  4. 4.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  6. 6.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?
  7. 7.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  9. 9.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  10. 10.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  11. 11.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?
  12. 12.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?
  13. 13.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  14. 14.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.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?
  16. 16.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  17. 17.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.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?
  19. 19.A leapfrog list starts 8, 8 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 7, 4 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 8, 1 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, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  23. 23.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  24. 24.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?
  25. 25.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?
  26. 26.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  27. 27.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  28. 28.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  29. 29.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  30. 30.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  31. 31.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  32. 32.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  33. 33.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?
  34. 34.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  37. 37.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  38. 38.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?
  39. 39.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  40. 40.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =

Answer key

  1. 616
  2. 803
  3. 407
  4. 979
  5. 1199
  6. 682
  7. 1199
  8. 814
  9. 1034
  10. 715
  11. 836
  12. 693
  13. 484
  14. 594
  15. 1199
  16. 671
  17. 605
  18. 198
  19. 1144
  20. 737
  21. 528
  22. 638
  23. 308
  24. 1111
  25. 814
  26. 528
  27. 880
  28. 495
  29. 1287
  30. 902
  31. 429
  32. 638
  33. 198
  34. 484
  35. 869
  36. 308
  37. 957
  38. 660
  39. 726
  40. 572

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