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 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 3.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.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?
- 5.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 6.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?
- 7.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?
- 8.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 10.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 11.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 12.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?
- 13.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
- 14.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 15.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
- 16.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 17.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 18.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
- 19.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 20.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 21.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?
- 22.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 23.A leapfrog list starts 4, 8 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): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
- 25.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 26.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
- 27.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 28.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 29.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 30.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 31.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 32.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?
- 33.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?
- 34.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?
- 35.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?
- 36.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 37.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?
- 38.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 40.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?
Answer key
- 473
- 638
- 836
- 704
- 1199
- 649
- 638
- 660
- 968
- 561
- 429
- 517
- 528
- 704
- 957
- 1067
- 418
- 858
- 341
- 583
- 319
- 1287
- 924
- 308
- 671
- 572
- 814
- 759
- 1001
- 1056
- 198
- 429
- 594
- 407
- 1067
- 374
- 759
- 781
- 902
- 451
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