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): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
- 2.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 3.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 4.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 5.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 7.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?
- 8.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?
- 9.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?
- 10.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?
- 11.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 12.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 13.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 14.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 15.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?
- 16.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 17.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 18.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 20.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 21.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?
- 22.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?
- 23.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?
- 24.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?
- 25.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?
- 26.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?
- 27.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
- 28.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?
- 29.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 30.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?
- 31.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 32.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 33.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 34.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 36.A leapfrog list starts 1, 5 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 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
Answer key
- 1089
- 880
- 198
- 429
- 671
- 869
- 1067
- 671
- 583
- 1111
- 1199
- 1056
- 957
- 231
- 1111
- 902
- 814
- 319
- 1001
- 825
- 770
- 638
- 418
- 517
- 704
- 627
- 1232
- 484
- 231
- 1144
- 737
- 891
- 1111
- 803
- 1144
- 495
- 726
- 561
- 396
- 781
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