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, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 2.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 3.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 5.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?
- 6.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?
- 7.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 8.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?
- 9.A leapfrog list starts 5, 7 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): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
- 11.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 12.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 13.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
- 14.A leapfrog list starts 3, 4 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): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. 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.A leapfrog list starts 6, 1 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 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 21.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 22.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?
- 23.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 24.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 25.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?
- 26.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 27.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 28.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
- 29.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 30.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 31.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.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?
- 33.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 34.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 35.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
- 36.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 38.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?
- 39.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?
- 40.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 143
- 748
- 847
- 924
- 451
- 143
- 1067
- 1144
- 891
- 649
- 759
- 968
- 517
- 517
- 693
- 429
- 418
- 737
- 638
- 825
- 561
- 891
- 737
- 517
- 770
- 726
- 374
- 836
- 847
- 594
- 671
- 1034
- 396
- 715
- 924
- 1144
- 726
- 484
- 1177
- 649
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