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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 567 · 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. 1.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  2. 2.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  3. 3.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  4. 4.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?
  5. 5.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?
  6. 6.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  7. 7.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  8. 8.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?
  9. 9.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  10. 10.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  11. 11.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?
  12. 12.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?
  13. 13.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?
  14. 14.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?
  15. 15.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  16. 16.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  17. 17.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  20. 20.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?
  21. 21.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  22. 22.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  23. 23.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  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. 25.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  28. 28.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  29. 29.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  31. 31.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?
  32. 32.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  33. 33.A leapfrog list starts 7, 6 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 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  36. 36.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?
  37. 37.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  38. 38.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.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?
  40. 40.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?

Answer key

  1. 583
  2. 627
  3. 429
  4. 517
  5. 495
  6. 1067
  7. 737
  8. 363
  9. 550
  10. 495
  11. 638
  12. 814
  13. 484
  14. 737
  15. 198
  16. 979
  17. 143
  18. 1067
  19. 957
  20. 726
  21. 880
  22. 660
  23. 891
  24. 198
  25. 671
  26. 473
  27. 715
  28. 781
  29. 528
  30. 583
  31. 374
  32. 253
  33. 913
  34. 693
  35. 539
  36. 341
  37. 616
  38. 770
  39. 847
  40. 506

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