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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 373 · 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 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  2. 2.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  5. 5.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  6. 6.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?
  7. 7.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?
  8. 8.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  10. 10.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?
  11. 11.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  12. 12.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  13. 13.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  14. 14.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  15. 15.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  16. 16.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?
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  19. 19.A leapfrog list starts 3, 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 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  22. 22.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  23. 23.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?
  24. 24.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  26. 26.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  27. 27.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  28. 28.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?
  29. 29.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  30. 30.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?
  31. 31.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  32. 32.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  33. 33.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  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 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  36. 36.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  38. 38.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?
  39. 39.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  40. 40.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?

Answer key

  1. 495
  2. 1122
  3. 1089
  4. 539
  5. 1111
  6. 891
  7. 748
  8. 407
  9. 429
  10. 759
  11. 451
  12. 891
  13. 1067
  14. 715
  15. 528
  16. 429
  17. 770
  18. 759
  19. 957
  20. 1012
  21. 473
  22. 649
  23. 715
  24. 462
  25. 451
  26. 363
  27. 836
  28. 671
  29. 781
  30. 869
  31. 880
  32. 583
  33. 946
  34. 693
  35. 979
  36. 473
  37. 506
  38. 286
  39. 803
  40. 1199

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