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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 364 · 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 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.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?
  3. 3.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  4. 4.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  6. 6.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?
  7. 7.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?
  8. 8.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  10. 10.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  11. 11.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  12. 12.A leapfrog list starts 5, 3 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, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  15. 15.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  16. 16.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?
  17. 17.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  18. 18.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?
  19. 19.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?
  20. 20.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?
  21. 21.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?
  22. 22.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  23. 23.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?
  24. 24.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  25. 25.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  26. 26.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  27. 27.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?
  28. 28.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?
  29. 29.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  30. 30.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?
  31. 31.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?
  32. 32.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?
  33. 33.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?
  34. 34.A leapfrog list starts 9, 7 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, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  36. 36.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  37. 37.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  38. 38.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  40. 40.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =

Answer key

  1. 1232
  2. 484
  3. 429
  4. 869
  5. 770
  6. 1199
  7. 825
  8. 561
  9. 825
  10. 935
  11. 1023
  12. 539
  13. 748
  14. 814
  15. 1144
  16. 748
  17. 946
  18. 341
  19. 1067
  20. 528
  21. 1089
  22. 847
  23. 363
  24. 803
  25. 649
  26. 858
  27. 924
  28. 693
  29. 1111
  30. 198
  31. 671
  32. 286
  33. 759
  34. 1111
  35. 957
  36. 605
  37. 143
  38. 1001
  39. 341
  40. 484

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