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 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.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?
- 3.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 4.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 5.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 7.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
- 8.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 9.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
- 11.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
- 12.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 13.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 14.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 16.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?
- 17.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?
- 18.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?
- 19.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 20.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?
- 21.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?
- 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.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 25.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 26.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?
- 27.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?
- 28.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?
- 29.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 30.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 31.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 32.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 33.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?
- 34.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?
- 35.A leapfrog list starts 9, 8 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 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 38.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?
- 39.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?
- 40.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
Answer key
- 1177
- 1067
- 539
- 473
- 506
- 231
- 649
- 583
- 704
- 1111
- 737
- 902
- 374
- 473
- 759
- 462
- 286
- 1287
- 726
- 583
- 484
- 726
- 770
- 913
- 638
- 869
- 638
- 231
- 847
- 627
- 924
- 715
- 374
- 1012
- 1199
- 627
- 495
- 451
- 759
- 319
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