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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 228 · 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. 1.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  2. 2.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?
  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.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  5. 5.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?
  6. 6.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?
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  9. 9.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?
  10. 10.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?
  11. 11.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  12. 12.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  13. 13.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  14. 14.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?
  15. 15.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?
  16. 16.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?
  17. 17.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  18. 18.A leapfrog list starts 2, 4 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 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  21. 21.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  22. 22.A leapfrog list starts 6, 9 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): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  24. 24.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  25. 25.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  26. 26.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  27. 27.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  28. 28.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  29. 29.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?
  30. 30.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  31. 31.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?
  32. 32.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  33. 33.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  34. 34.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  36. 36.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  37. 37.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?
  38. 38.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  40. 40.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?

Answer key

  1. 814
  2. 528
  3. 319
  4. 869
  5. 770
  6. 671
  7. 605
  8. 649
  9. 726
  10. 418
  11. 957
  12. 539
  13. 550
  14. 792
  15. 605
  16. 1023
  17. 1001
  18. 462
  19. 847
  20. 1034
  21. 946
  22. 1122
  23. 968
  24. 374
  25. 847
  26. 143
  27. 506
  28. 1199
  29. 319
  30. 528
  31. 550
  32. 825
  33. 1012
  34. 847
  35. 198
  36. 1067
  37. 957
  38. 341
  39. 484
  40. 308

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