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): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
- 2.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 3.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 4.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 5.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?
- 6.A leapfrog list starts 3, 5 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 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 9.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
- 10.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?
- 11.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 12.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
- 13.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
- 14.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 15.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 16.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 17.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
- 18.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 19.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 20.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?
- 21.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?
- 22.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 23.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?
- 24.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?
- 25.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?
- 26.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 27.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?
- 28.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
- 29.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 30.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?
- 31.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
- 32.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
- 33.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 34.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 35.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 36.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 37.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 38.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?
- 39.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
- 40.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
Answer key
- 869
- 1111
- 1199
- 605
- 803
- 605
- 231
- 924
- 484
- 748
- 704
- 891
- 495
- 231
- 759
- 308
- 935
- 671
- 418
- 572
- 198
- 418
- 649
- 253
- 759
- 946
- 737
- 594
- 847
- 671
- 517
- 374
- 968
- 407
- 1034
- 561
- 484
- 572
- 902
- 1001
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