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.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?
- 2.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 3.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
- 4.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 5.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
- 6.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 7.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
- 8.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 9.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?
- 10.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
- 12.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 13.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 14.A leapfrog list starts 2, 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): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
- 16.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?
- 17.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
- 18.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 19.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 20.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 21.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 22.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?
- 23.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?
- 24.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 25.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?
- 26.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 27.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 28.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?
- 29.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?
- 30.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 31.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 33.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 34.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 35.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 36.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.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?
- 38.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 39.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?
- 40.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
Answer key
- 418
- 473
- 319
- 770
- 748
- 649
- 363
- 1067
- 462
- 1067
- 495
- 682
- 726
- 814
- 506
- 429
- 638
- 671
- 836
- 847
- 253
- 660
- 869
- 715
- 374
- 143
- 286
- 451
- 308
- 462
- 1177
- 957
- 143
- 231
- 363
- 1023
- 1089
- 451
- 341
- 561
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