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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 822 · 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, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.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?
  3. 3.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  4. 4.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?
  5. 5.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  6. 6.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  8. 8.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  10. 10.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  11. 11.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  14. 14.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?
  15. 15.A leapfrog list starts 3, 9 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): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  17. 17.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?
  18. 18.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?
  19. 19.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?
  20. 20.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  21. 21.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  22. 22.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?
  23. 23.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  25. 25.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?
  26. 26.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  27. 27.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  28. 28.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  30. 30.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  32. 32.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  33. 33.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.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?
  39. 39.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  40. 40.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?

Answer key

  1. 847
  2. 737
  3. 517
  4. 715
  5. 825
  6. 979
  7. 682
  8. 836
  9. 616
  10. 495
  11. 638
  12. 594
  13. 759
  14. 869
  15. 957
  16. 594
  17. 396
  18. 451
  19. 649
  20. 759
  21. 1001
  22. 957
  23. 1111
  24. 638
  25. 671
  26. 462
  27. 462
  28. 627
  29. 286
  30. 396
  31. 803
  32. 539
  33. 649
  34. 1089
  35. 858
  36. 231
  37. 660
  38. 286
  39. 924
  40. 913

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