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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 754 · 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 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  2. 2.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  3. 3.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  4. 4.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  5. 5.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?
  6. 6.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  7. 7.A leapfrog list starts 1, 8 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, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  10. 10.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?
  11. 11.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?
  12. 12.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  13. 13.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?
  14. 14.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?
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  17. 17.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?
  18. 18.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?
  19. 19.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  20. 20.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?
  21. 21.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  23. 23.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  25. 25.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?
  26. 26.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  28. 28.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?
  29. 29.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  30. 30.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?
  31. 31.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.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?
  34. 34.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  35. 35.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?
  36. 36.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  37. 37.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  38. 38.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  40. 40.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?

Answer key

  1. 803
  2. 957
  3. 286
  4. 561
  5. 594
  6. 1012
  7. 759
  8. 583
  9. 682
  10. 627
  11. 572
  12. 517
  13. 891
  14. 693
  15. 649
  16. 1232
  17. 671
  18. 517
  19. 979
  20. 1067
  21. 693
  22. 649
  23. 1023
  24. 1089
  25. 418
  26. 253
  27. 748
  28. 374
  29. 572
  30. 946
  31. 1111
  32. 649
  33. 363
  34. 693
  35. 913
  36. 319
  37. 418
  38. 1001
  39. 1287
  40. 528

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