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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 121 · 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 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.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?
  3. 3.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.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?
  5. 5.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?
  6. 6.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?
  7. 7.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  8. 8.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  9. 9.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?
  10. 10.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  11. 11.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  12. 12.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  13. 13.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  16. 16.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?
  17. 17.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  18. 18.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  20. 20.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  21. 21.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.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?
  23. 23.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  24. 24.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  25. 25.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?
  26. 26.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?
  27. 27.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  28. 28.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?
  29. 29.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  30. 30.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  31. 31.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  32. 32.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  33. 33.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  34. 34.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?
  35. 35.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  36. 36.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?
  37. 37.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?
  38. 38.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  39. 39.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =

Answer key

  1. 407
  2. 858
  3. 572
  4. 1034
  5. 869
  6. 550
  7. 737
  8. 825
  9. 770
  10. 1012
  11. 319
  12. 506
  13. 407
  14. 891
  15. 946
  16. 583
  17. 517
  18. 1023
  19. 231
  20. 847
  21. 946
  22. 660
  23. 693
  24. 715
  25. 715
  26. 418
  27. 682
  28. 880
  29. 946
  30. 1144
  31. 473
  32. 363
  33. 374
  34. 308
  35. 1034
  36. 671
  37. 374
  38. 935
  39. 891
  40. 418

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