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 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 2.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 3.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 4.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?
- 5.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 6.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 7.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?
- 8.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 9.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?
- 10.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 12.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 13.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?
- 14.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 15.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 17.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?
- 18.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?
- 19.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 21.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.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?
- 23.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?
- 24.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
- 25.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
- 27.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 29.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 30.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?
- 31.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 32.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?
- 33.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?
- 34.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 35.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 36.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?
- 37.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 38.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?
- 39.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
Answer key
- 407
- 924
- 286
- 583
- 748
- 396
- 528
- 605
- 748
- 286
- 253
- 484
- 880
- 627
- 627
- 649
- 253
- 374
- 1287
- 198
- 374
- 902
- 473
- 1199
- 1111
- 583
- 253
- 319
- 979
- 341
- 737
- 561
- 759
- 1111
- 682
- 231
- 858
- 671
- 407
- 935
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