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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 375 · 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. 1.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  3. 3.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  4. 4.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  5. 5.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  6. 6.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  8. 8.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  9. 9.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.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?
  11. 11.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?
  12. 12.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?
  13. 13.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?
  14. 14.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?
  15. 15.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?
  16. 16.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?
  17. 17.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  19. 19.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  20. 20.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?
  21. 21.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  22. 22.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  23. 23.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  24. 24.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?
  25. 25.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?
  26. 26.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  28. 28.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?
  29. 29.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  30. 30.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  31. 31.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?
  32. 32.A leapfrog list starts 1, 2 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): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  34. 34.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  35. 35.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?
  36. 36.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?
  37. 37.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  38. 38.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  39. 39.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  40. 40.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?

Answer key

  1. 781
  2. 671
  3. 715
  4. 660
  5. 880
  6. 308
  7. 253
  8. 847
  9. 792
  10. 429
  11. 924
  12. 396
  13. 572
  14. 341
  15. 506
  16. 308
  17. 1056
  18. 638
  19. 935
  20. 682
  21. 726
  22. 231
  23. 198
  24. 649
  25. 627
  26. 891
  27. 825
  28. 1089
  29. 308
  30. 1199
  31. 253
  32. 231
  33. 1001
  34. 473
  35. 517
  36. 341
  37. 836
  38. 429
  39. 1056
  40. 693

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