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 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 3.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
- 4.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 5.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
- 6.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 7.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 9.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?
- 10.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?
- 11.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 12.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 13.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 14.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 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?
- 16.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 17.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 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.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?
- 20.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 22.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 23.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.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?
- 25.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?
- 26.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
- 27.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 28.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 29.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 31.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?
- 32.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?
- 33.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
- 34.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?
- 35.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?
- 36.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 37.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?
- 38.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?
- 39.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 40.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
Answer key
- 374
- 836
- 979
- 418
- 792
- 341
- 1001
- 880
- 1111
- 814
- 759
- 693
- 583
- 891
- 1111
- 572
- 1001
- 319
- 1287
- 583
- 748
- 572
- 407
- 1144
- 396
- 539
- 550
- 902
- 682
- 869
- 781
- 484
- 759
- 308
- 935
- 198
- 737
- 506
- 594
- 726
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