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 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 3.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 4.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 5.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.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?
- 7.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 9.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 10.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
- 11.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
- 12.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 13.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?
- 14.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?
- 15.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
- 16.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 17.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
- 18.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 19.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?
- 20.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?
- 21.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?
- 22.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
- 23.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 24.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 25.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 26.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?
- 27.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?
- 28.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
- 29.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 30.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 31.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 33.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?
- 34.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 35.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 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.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?
- 39.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?
- 40.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
Answer key
- 528
- 1122
- 891
- 1177
- 715
- 572
- 231
- 1023
- 704
- 1023
- 814
- 528
- 693
- 1067
- 528
- 1287
- 308
- 1056
- 902
- 913
- 660
- 1012
- 1144
- 759
- 726
- 484
- 726
- 671
- 1199
- 473
- 572
- 462
- 803
- 902
- 825
- 1012
- 341
- 286
- 462
- 770
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