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
- 1.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 2.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
- 3.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?
- 4.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 5.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
- 6.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?
- 7.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?
- 8.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 9.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 10.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 12.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
- 13.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?
- 14.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
- 15.A leapfrog list starts 9, 5 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): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
- 17.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 18.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?
- 19.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?
- 20.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
- 21.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 22.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 23.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?
- 24.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?
- 25.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 26.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?
- 27.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?
- 28.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 29.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.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?
- 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.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?
- 33.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?
- 34.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?
- 35.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 36.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 37.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 38.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.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?
- 40.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
Answer key
- 231
- 253
- 1001
- 484
- 792
- 462
- 671
- 858
- 913
- 704
- 286
- 605
- 561
- 979
- 935
- 693
- 715
- 198
- 572
- 726
- 1199
- 946
- 759
- 484
- 1144
- 649
- 616
- 880
- 1144
- 143
- 803
- 286
- 198
- 517
- 319
- 308
- 341
- 341
- 869
- 495
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