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
- 1.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 2.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 3.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?
- 4.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?
- 5.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 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.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
- 8.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 9.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 10.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 11.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 12.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?
- 13.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?
- 14.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?
- 15.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?
- 16.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 17.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?
- 18.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
- 19.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 21.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?
- 22.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 23.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 26.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 27.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 28.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?
- 29.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.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?
- 31.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 32.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.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?
- 34.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
- 35.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 36.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?
- 37.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 38.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 39.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?
- 40.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
Answer key
- 1199
- 869
- 231
- 396
- 583
- 143
- 1287
- 583
- 583
- 1023
- 825
- 759
- 374
- 1144
- 308
- 484
- 495
- 506
- 913
- 902
- 506
- 1177
- 968
- 979
- 506
- 341
- 429
- 638
- 759
- 1177
- 1122
- 935
- 726
- 198
- 957
- 693
- 594
- 814
- 1199
- 759
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