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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 59 · 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. 1.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  3. 3.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  4. 4.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  6. 6.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?
  7. 7.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  9. 9.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  10. 10.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?
  11. 11.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  13. 13.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  14. 14.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  16. 16.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  17. 17.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  20. 20.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  21. 21.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  22. 22.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  23. 23.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  24. 24.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  25. 25.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?
  26. 26.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  27. 27.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  29. 29.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  30. 30.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  31. 31.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?
  32. 32.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  38. 38.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?
  39. 39.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  40. 40.A leapfrog list starts 9, 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. 374
  2. 968
  3. 935
  4. 341
  5. 891
  6. 1023
  7. 891
  8. 407
  9. 198
  10. 781
  11. 605
  12. 1012
  13. 880
  14. 847
  15. 451
  16. 396
  17. 660
  18. 308
  19. 341
  20. 836
  21. 462
  22. 1089
  23. 847
  24. 803
  25. 726
  26. 671
  27. 473
  28. 759
  29. 561
  30. 594
  31. 627
  32. 363
  33. 550
  34. 748
  35. 605
  36. 781
  37. 495
  38. 869
  39. 616
  40. 583

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