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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 846 · 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 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  2. 2.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?
  3. 3.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  5. 5.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?
  6. 6.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  7. 7.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?
  8. 8.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  10. 10.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  11. 11.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?
  12. 12.A leapfrog list starts 8, 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 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  15. 15.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?
  16. 16.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?
  17. 17.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  18. 18.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  19. 19.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  20. 20.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?
  21. 21.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  22. 22.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  23. 23.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?
  24. 24.A leapfrog list starts 6, 1 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): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  26. 26.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  27. 27.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?
  28. 28.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  29. 29.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  31. 31.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?
  32. 32.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?
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.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?
  38. 38.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  39. 39.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?

Answer key

  1. 671
  2. 286
  3. 649
  4. 396
  5. 308
  6. 341
  7. 671
  8. 1287
  9. 1287
  10. 781
  11. 583
  12. 704
  13. 506
  14. 627
  15. 594
  16. 682
  17. 869
  18. 880
  19. 726
  20. 1177
  21. 770
  22. 1012
  23. 803
  24. 418
  25. 253
  26. 363
  27. 231
  28. 847
  29. 814
  30. 1111
  31. 363
  32. 198
  33. 759
  34. 891
  35. 693
  36. 814
  37. 1001
  38. 1001
  39. 1122
  40. 616

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