Leapfrog Sum Trick Worksheet
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
- 1.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 2.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
- 3.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?
- 4.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 5.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
- 6.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 7.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 8.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
- 9.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
- 11.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
- 12.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
- 13.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 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.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?
- 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.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 19.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 20.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?
- 21.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 22.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?
- 23.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.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?
- 25.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
- 26.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 27.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 30.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 31.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 33.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 34.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 35.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?
- 36.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?
- 37.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 38.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 39.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
Answer key
- 451
- 847
- 286
- 671
- 902
- 814
- 374
- 1287
- 1056
- 924
- 583
- 1177
- 913
- 869
- 968
- 374
- 737
- 847
- 891
- 143
- 1056
- 583
- 594
- 198
- 429
- 605
- 616
- 308
- 693
- 1144
- 979
- 924
- 495
- 407
- 451
- 825
- 781
- 198
- 561
- 462
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