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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 47 · 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. 1.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  3. 3.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?
  4. 4.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?
  5. 5.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?
  6. 6.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  7. 7.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  9. 9.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  10. 10.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  11. 11.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  12. 12.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  13. 13.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  15. 15.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  16. 16.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  17. 17.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?
  18. 18.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?
  19. 19.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?
  20. 20.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?
  21. 21.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  22. 22.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?
  23. 23.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?
  24. 24.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  25. 25.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?
  26. 26.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  27. 27.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  28. 28.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  31. 31.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  32. 32.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  37. 37.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?
  38. 38.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  39. 39.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  40. 40.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?

Answer key

  1. 253
  2. 517
  3. 286
  4. 550
  5. 1199
  6. 374
  7. 1232
  8. 924
  9. 528
  10. 308
  11. 649
  12. 627
  13. 924
  14. 517
  15. 583
  16. 660
  17. 506
  18. 902
  19. 308
  20. 792
  21. 869
  22. 649
  23. 748
  24. 1122
  25. 1111
  26. 1012
  27. 1034
  28. 869
  29. 253
  30. 1067
  31. 484
  32. 847
  33. 726
  34. 143
  35. 594
  36. 594
  37. 946
  38. 671
  39. 836
  40. 847

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