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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 718 · 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 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  3. 3.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  4. 4.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?
  5. 5.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?
  6. 6.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  7. 7.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?
  8. 8.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  9. 9.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  11. 11.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  12. 12.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  16. 16.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  17. 17.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  18. 18.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  19. 19.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  20. 20.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  22. 22.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  23. 23.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?
  24. 24.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  28. 28.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?
  29. 29.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  31. 31.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.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?
  33. 33.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  35. 35.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  36. 36.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?
  37. 37.A leapfrog list starts 8, 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 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  40. 40.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =

Answer key

  1. 495
  2. 935
  3. 429
  4. 968
  5. 803
  6. 682
  7. 143
  8. 1089
  9. 770
  10. 913
  11. 803
  12. 1287
  13. 583
  14. 682
  15. 1012
  16. 924
  17. 759
  18. 539
  19. 759
  20. 836
  21. 396
  22. 583
  23. 847
  24. 473
  25. 957
  26. 902
  27. 627
  28. 517
  29. 374
  30. 1111
  31. 682
  32. 1287
  33. 968
  34. 660
  35. 649
  36. 583
  37. 968
  38. 594
  39. 253
  40. 693

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