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, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
- 2.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
- 3.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 4.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 5.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 6.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?
- 7.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?
- 8.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?
- 9.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?
- 10.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?
- 11.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 12.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 13.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 15.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 16.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?
- 17.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 18.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 19.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 20.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 22.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 23.A leapfrog list starts 4, 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, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.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?
- 26.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 27.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?
- 28.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
- 29.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.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?
- 31.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 32.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?
- 33.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 34.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?
- 35.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 36.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
- 37.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.A leapfrog list starts 2, 8 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 1, 1 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): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
Answer key
- 649
- 704
- 935
- 946
- 979
- 231
- 429
- 396
- 1144
- 253
- 781
- 418
- 902
- 726
- 957
- 1287
- 495
- 506
- 792
- 594
- 880
- 627
- 748
- 451
- 1232
- 814
- 583
- 847
- 1056
- 671
- 594
- 253
- 561
- 726
- 1177
- 308
- 715
- 814
- 143
- 319
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