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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 285 · 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 9, 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 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  3. 3.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  4. 4.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?
  5. 5.A leapfrog list starts 7, 4 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): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  7. 7.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  9. 9.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?
  10. 10.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  11. 11.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?
  12. 12.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  13. 13.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  14. 14.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?
  15. 15.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  17. 17.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  19. 19.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  20. 20.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  21. 21.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.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?
  23. 23.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  24. 24.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?
  25. 25.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?
  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): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  28. 28.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?
  29. 29.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  30. 30.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?
  31. 31.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?
  32. 32.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?
  33. 33.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?
  34. 34.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  35. 35.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?
  36. 36.A leapfrog list starts 2, 2 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 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  39. 39.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  40. 40.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?

Answer key

  1. 1287
  2. 638
  3. 528
  4. 341
  5. 737
  6. 1034
  7. 506
  8. 836
  9. 319
  10. 308
  11. 1056
  12. 429
  13. 671
  14. 803
  15. 1012
  16. 748
  17. 924
  18. 1177
  19. 495
  20. 1056
  21. 869
  22. 616
  23. 374
  24. 715
  25. 1012
  26. 902
  27. 957
  28. 924
  29. 781
  30. 880
  31. 671
  32. 539
  33. 660
  34. 792
  35. 418
  36. 286
  37. 484
  38. 935
  39. 814
  40. 319

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