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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 606 · 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.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?
  2. 2.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  3. 3.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?
  4. 4.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?
  5. 5.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  6. 6.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?
  7. 7.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  9. 9.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  10. 10.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?
  11. 11.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  12. 12.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?
  13. 13.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  14. 14.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  16. 16.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  17. 17.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  20. 20.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?
  21. 21.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?
  22. 22.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  23. 23.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  24. 24.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?
  25. 25.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  26. 26.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?
  27. 27.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?
  28. 28.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  29. 29.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  30. 30.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  31. 31.A leapfrog list starts 2, 9 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): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  33. 33.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  35. 35.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  36. 36.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  37. 37.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?
  38. 38.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  40. 40.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?

Answer key

  1. 286
  2. 616
  3. 748
  4. 341
  5. 1001
  6. 792
  7. 1177
  8. 495
  9. 550
  10. 726
  11. 924
  12. 308
  13. 253
  14. 847
  15. 407
  16. 539
  17. 891
  18. 715
  19. 594
  20. 1067
  21. 495
  22. 363
  23. 143
  24. 825
  25. 407
  26. 1199
  27. 605
  28. 660
  29. 319
  30. 506
  31. 902
  32. 770
  33. 143
  34. 451
  35. 231
  36. 1012
  37. 407
  38. 1287
  39. 561
  40. 814

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