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
- 1.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 2.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
- 3.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 4.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 5.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 7.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?
- 8.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 9.A leapfrog list starts 9, 3 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): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
- 11.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 12.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?
- 13.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 14.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 15.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?
- 16.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?
- 17.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?
- 18.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 19.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
- 20.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 21.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 22.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?
- 23.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 24.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 25.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?
- 26.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 27.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?
- 28.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?
- 29.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
- 30.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?
- 31.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.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?
- 33.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 34.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 35.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 36.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 38.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 39.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?
- 40.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?
Answer key
- 550
- 935
- 341
- 539
- 1122
- 759
- 825
- 814
- 759
- 803
- 803
- 891
- 704
- 407
- 671
- 572
- 869
- 517
- 1111
- 561
- 286
- 396
- 143
- 968
- 418
- 451
- 847
- 660
- 561
- 616
- 726
- 649
- 913
- 429
- 858
- 781
- 473
- 451
- 1067
- 847
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