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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 734 · 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.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?
  2. 2.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  3. 3.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  4. 4.A leapfrog list starts 5, 5 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 8, 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): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  7. 7.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  8. 8.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?
  9. 9.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  10. 10.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  11. 11.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?
  12. 12.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.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?
  14. 14.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  15. 15.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?
  16. 16.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  17. 17.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  18. 18.A leapfrog list starts 2, 2 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): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  20. 20.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?
  21. 21.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  23. 23.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?
  24. 24.A leapfrog list starts 3, 8 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, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  28. 28.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?
  29. 29.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?
  30. 30.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  31. 31.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?
  32. 32.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  33. 33.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  34. 34.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?
  35. 35.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  36. 36.A leapfrog list starts 1, 8 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 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  39. 39.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  40. 40.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?

Answer key

  1. 429
  2. 1089
  3. 539
  4. 715
  5. 880
  6. 759
  7. 616
  8. 462
  9. 583
  10. 1012
  11. 506
  12. 451
  13. 1199
  14. 286
  15. 671
  16. 891
  17. 759
  18. 286
  19. 143
  20. 319
  21. 913
  22. 748
  23. 1199
  24. 869
  25. 1067
  26. 451
  27. 231
  28. 506
  29. 1232
  30. 1001
  31. 484
  32. 605
  33. 781
  34. 528
  35. 286
  36. 759
  37. 858
  38. 814
  39. 847
  40. 638

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