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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 548 · 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 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  4. 4.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  6. 6.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  7. 7.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  8. 8.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  11. 11.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  12. 12.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  13. 13.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?
  14. 14.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  16. 16.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?
  17. 17.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?
  18. 18.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  21. 21.A leapfrog list starts 1, 6 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): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  23. 23.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  24. 24.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  25. 25.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?
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  28. 28.A leapfrog list starts 1, 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 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  31. 31.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?
  32. 32.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?
  33. 33.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  38. 38.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  39. 39.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  40. 40.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?

Answer key

  1. 957
  2. 814
  3. 319
  4. 451
  5. 1034
  6. 1012
  7. 693
  8. 528
  9. 1056
  10. 957
  11. 1199
  12. 836
  13. 418
  14. 1067
  15. 979
  16. 759
  17. 1012
  18. 506
  19. 231
  20. 880
  21. 583
  22. 671
  23. 528
  24. 1287
  25. 517
  26. 616
  27. 473
  28. 759
  29. 649
  30. 231
  31. 594
  32. 759
  33. 605
  34. 957
  35. 781
  36. 726
  37. 1067
  38. 968
  39. 759
  40. 550

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