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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 553 · 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. 1.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  2. 2.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?
  3. 3.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  4. 4.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.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?
  6. 6.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?
  7. 7.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  8. 8.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?
  9. 9.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  10. 10.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  11. 11.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  13. 13.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  14. 14.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  15. 15.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?
  16. 16.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  17. 17.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.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?
  19. 19.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  20. 20.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.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?
  22. 22.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  27. 27.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?
  28. 28.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?
  29. 29.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?
  30. 30.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  31. 31.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?
  32. 32.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  33. 33.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?
  34. 34.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  35. 35.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  37. 37.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?
  38. 38.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?
  39. 39.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?
  40. 40.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =

Answer key

  1. 539
  2. 825
  3. 957
  4. 814
  5. 1144
  6. 924
  7. 649
  8. 616
  9. 1111
  10. 715
  11. 231
  12. 693
  13. 781
  14. 803
  15. 495
  16. 407
  17. 451
  18. 957
  19. 594
  20. 704
  21. 759
  22. 528
  23. 660
  24. 539
  25. 583
  26. 1023
  27. 781
  28. 517
  29. 605
  30. 1067
  31. 374
  32. 528
  33. 407
  34. 759
  35. 671
  36. 792
  37. 341
  38. 759
  39. 726
  40. 759

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