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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 751 · 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.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?
  3. 3.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?
  4. 4.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  6. 6.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?
  7. 7.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  8. 8.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  9. 9.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?
  10. 10.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?
  11. 11.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?
  12. 12.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  13. 13.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  14. 14.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  15. 15.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  16. 16.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  18. 18.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  19. 19.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  21. 21.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?
  22. 22.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  23. 23.A leapfrog list starts 2, 5 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 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  26. 26.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  28. 28.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?
  29. 29.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?
  30. 30.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?
  31. 31.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?
  32. 32.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?
  33. 33.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  34. 34.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  36. 36.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?
  37. 37.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  38. 38.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?
  39. 39.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  40. 40.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?

Answer key

  1. 429
  2. 671
  3. 726
  4. 627
  5. 1001
  6. 1177
  7. 506
  8. 1144
  9. 231
  10. 495
  11. 715
  12. 1144
  13. 561
  14. 803
  15. 308
  16. 803
  17. 935
  18. 583
  19. 231
  20. 825
  21. 484
  22. 539
  23. 550
  24. 660
  25. 704
  26. 671
  27. 814
  28. 594
  29. 143
  30. 759
  31. 407
  32. 308
  33. 814
  34. 198
  35. 253
  36. 869
  37. 671
  38. 638
  39. 1034
  40. 1199

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