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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 842 · 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. 1.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  2. 2.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  3. 3.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  4. 4.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?
  5. 5.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?
  6. 6.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  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.A leapfrog list starts 2, 8 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.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  12. 12.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?
  13. 13.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?
  14. 14.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  15. 15.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  20. 20.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  22. 22.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?
  23. 23.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  26. 26.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?
  27. 27.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  28. 28.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?
  29. 29.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  30. 30.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?
  31. 31.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  33. 33.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?
  34. 34.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?
  35. 35.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  36. 36.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  38. 38.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?
  39. 39.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  40. 40.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =

Answer key

  1. 363
  2. 682
  3. 506
  4. 759
  5. 649
  6. 363
  7. 858
  8. 770
  9. 814
  10. 957
  11. 627
  12. 473
  13. 407
  14. 847
  15. 143
  16. 374
  17. 1023
  18. 836
  19. 902
  20. 627
  21. 462
  22. 550
  23. 594
  24. 374
  25. 396
  26. 572
  27. 891
  28. 484
  29. 715
  30. 726
  31. 451
  32. 968
  33. 308
  34. 319
  35. 748
  36. 858
  37. 847
  38. 319
  39. 935
  40. 660

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