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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 279 · 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): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  2. 2.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  4. 4.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  6. 6.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?
  7. 7.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?
  8. 8.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?
  9. 9.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  12. 12.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  13. 13.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  14. 14.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.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?
  16. 16.A leapfrog list starts 4, 2 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): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  18. 18.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  20. 20.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?
  21. 21.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  22. 22.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  23. 23.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  24. 24.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  25. 25.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  26. 26.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  27. 27.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  28. 28.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  29. 29.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  30. 30.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  31. 31.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?
  32. 32.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?
  33. 33.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?
  34. 34.A leapfrog list starts 2, 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, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  36. 36.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  37. 37.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  38. 38.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?
  39. 39.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  40. 40.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?

Answer key

  1. 1199
  2. 583
  3. 627
  4. 143
  5. 528
  6. 319
  7. 198
  8. 638
  9. 594
  10. 737
  11. 1001
  12. 473
  13. 462
  14. 462
  15. 473
  16. 396
  17. 539
  18. 715
  19. 682
  20. 638
  21. 506
  22. 561
  23. 759
  24. 1232
  25. 902
  26. 539
  27. 550
  28. 616
  29. 682
  30. 1023
  31. 880
  32. 1199
  33. 517
  34. 726
  35. 781
  36. 979
  37. 407
  38. 605
  39. 869
  40. 528

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