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): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
- 2.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 3.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 4.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?
- 5.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?
- 6.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 7.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?
- 8.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 9.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 10.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?
- 11.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 12.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 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?
- 14.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 15.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
- 16.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 17.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 19.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?
- 20.A leapfrog list starts 6, 9 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): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
- 22.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?
- 23.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
- 24.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 25.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
- 26.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 27.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?
- 28.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?
- 29.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?
- 30.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
- 31.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 32.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 33.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 34.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 35.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?
- 36.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?
- 37.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 38.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 39.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?
- 40.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
Answer key
- 671
- 1177
- 671
- 880
- 1001
- 858
- 759
- 1199
- 374
- 891
- 946
- 781
- 561
- 638
- 583
- 946
- 1034
- 759
- 308
- 1122
- 1034
- 726
- 847
- 506
- 968
- 847
- 143
- 957
- 869
- 594
- 616
- 957
- 528
- 759
- 1012
- 363
- 341
- 1111
- 605
- 407
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