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.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?
- 3.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?
- 4.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 5.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
- 6.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 7.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 8.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
- 9.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 10.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?
- 11.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?
- 12.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 13.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?
- 14.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 15.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
- 16.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 17.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 18.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 19.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 20.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?
- 21.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?
- 22.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 23.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 24.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
- 26.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 27.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 28.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 30.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 31.A leapfrog list starts 7, 4 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): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
- 33.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?
- 34.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?
- 35.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?
- 36.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?
- 37.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 38.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?
- 39.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?
- 40.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
Answer key
- 418
- 506
- 935
- 374
- 473
- 792
- 231
- 1177
- 407
- 374
- 1067
- 957
- 319
- 858
- 957
- 1067
- 1023
- 198
- 638
- 792
- 1144
- 726
- 1001
- 902
- 627
- 572
- 550
- 693
- 737
- 748
- 737
- 902
- 363
- 495
- 143
- 572
- 341
- 638
- 726
- 539
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