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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 988 · 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. 1.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  2. 2.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  4. 4.A leapfrog list starts 7, 6 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): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  6. 6.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  7. 7.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.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?
  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, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  12. 12.A leapfrog list starts 4, 1 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): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  14. 14.A leapfrog list starts 6, 1 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): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  16. 16.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  17. 17.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  18. 18.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  19. 19.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  22. 22.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  24. 24.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  26. 26.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  27. 27.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  28. 28.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  31. 31.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?
  32. 32.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  33. 33.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  34. 34.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?
  35. 35.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?
  36. 36.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  37. 37.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?
  38. 38.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  39. 39.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  40. 40.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?

Answer key

  1. 957
  2. 759
  3. 506
  4. 913
  5. 572
  6. 308
  7. 561
  8. 1199
  9. 286
  10. 484
  11. 143
  12. 308
  13. 770
  14. 418
  15. 1034
  16. 198
  17. 396
  18. 407
  19. 319
  20. 1089
  21. 1144
  22. 1177
  23. 363
  24. 671
  25. 836
  26. 792
  27. 473
  28. 539
  29. 231
  30. 891
  31. 836
  32. 715
  33. 495
  34. 198
  35. 374
  36. 814
  37. 1001
  38. 759
  39. 847
  40. 616

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