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.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.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?
- 3.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 5.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 6.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 8.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 9.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?
- 10.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
- 11.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 12.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?
- 13.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 15.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 16.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?
- 17.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 18.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
- 20.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 22.A leapfrog list starts 6, 2 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 1, 1 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): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 25.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 26.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 27.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?
- 28.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 29.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?
- 30.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 31.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?
- 32.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?
- 33.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?
- 34.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 35.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
- 36.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 37.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.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?
- 39.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 40.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
Answer key
- 605
- 891
- 198
- 748
- 143
- 847
- 341
- 671
- 1089
- 583
- 1056
- 726
- 1089
- 1001
- 1199
- 561
- 869
- 484
- 1199
- 968
- 561
- 506
- 143
- 451
- 605
- 781
- 286
- 253
- 979
- 550
- 660
- 858
- 253
- 649
- 1144
- 792
- 671
- 880
- 913
- 1111
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