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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 894 · 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. 1.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  3. 3.A leapfrog list starts 6, 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 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  6. 6.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  7. 7.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  8. 8.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  10. 10.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.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?
  12. 12.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  13. 13.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?
  14. 14.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  19. 19.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?
  20. 20.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  21. 21.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?
  22. 22.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  23. 23.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  24. 24.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  25. 25.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?
  26. 26.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  27. 27.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  29. 29.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  32. 32.A leapfrog list starts 5, 3 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, 9 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): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  35. 35.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?
  36. 36.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  37. 37.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?
  38. 38.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?

Answer key

  1. 1111
  2. 1056
  3. 946
  4. 781
  5. 957
  6. 319
  7. 858
  8. 682
  9. 396
  10. 847
  11. 506
  12. 913
  13. 594
  14. 1023
  15. 1287
  16. 484
  17. 517
  18. 1177
  19. 231
  20. 836
  21. 561
  22. 583
  23. 847
  24. 649
  25. 1177
  26. 935
  27. 759
  28. 363
  29. 572
  30. 726
  31. 506
  32. 539
  33. 957
  34. 286
  35. 748
  36. 869
  37. 726
  38. 1144
  39. 1111
  40. 429

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