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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 686 · 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 4, 5 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 7, 3 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 8, 2 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 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  6. 6.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?
  7. 7.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  8. 8.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  10. 10.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  14. 14.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?
  15. 15.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  16. 16.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?
  17. 17.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  20. 20.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  21. 21.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  22. 22.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?
  23. 23.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  24. 24.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  26. 26.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  27. 27.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  28. 28.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  29. 29.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  31. 31.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  32. 32.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?
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  37. 37.A leapfrog list starts 4, 6 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 7, 5 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 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =

Answer key

  1. 660
  2. 649
  3. 616
  4. 1023
  5. 638
  6. 594
  7. 374
  8. 913
  9. 418
  10. 979
  11. 583
  12. 1111
  13. 1067
  14. 539
  15. 286
  16. 143
  17. 198
  18. 1199
  19. 539
  20. 1144
  21. 1122
  22. 550
  23. 1001
  24. 1012
  25. 484
  26. 143
  27. 1232
  28. 1089
  29. 1232
  30. 583
  31. 1111
  32. 935
  33. 143
  34. 583
  35. 759
  36. 1001
  37. 748
  38. 825
  39. 396
  40. 715

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