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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 136 · 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 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  4. 4.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?
  5. 5.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?
  6. 6.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?
  7. 7.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  9. 9.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  10. 10.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?
  11. 11.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  13. 13.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  14. 14.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?
  15. 15.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?
  16. 16.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?
  17. 17.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  19. 19.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?
  20. 20.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  21. 21.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  22. 22.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  24. 24.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  25. 25.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?
  26. 26.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  27. 27.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  28. 28.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  29. 29.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  32. 32.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?
  33. 33.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  34. 34.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  35. 35.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?
  36. 36.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  38. 38.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  39. 39.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  40. 40.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?

Answer key

  1. 726
  2. 1034
  3. 671
  4. 550
  5. 550
  6. 418
  7. 550
  8. 770
  9. 286
  10. 1012
  11. 979
  12. 902
  13. 594
  14. 605
  15. 407
  16. 792
  17. 198
  18. 572
  19. 583
  20. 462
  21. 902
  22. 880
  23. 869
  24. 946
  25. 539
  26. 143
  27. 198
  28. 418
  29. 715
  30. 858
  31. 924
  32. 1067
  33. 539
  34. 1089
  35. 506
  36. 924
  37. 660
  38. 781
  39. 1001
  40. 1111

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