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 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 3.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?
- 4.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
- 5.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 6.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 7.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
- 8.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?
- 9.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 11.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
- 12.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?
- 13.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?
- 14.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 15.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?
- 16.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
- 17.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 18.A leapfrog list starts 2, 1 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 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 21.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 22.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?
- 23.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?
- 24.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 25.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 26.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?
- 27.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 28.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?
- 29.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 30.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 31.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 32.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 33.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?
- 34.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?
- 35.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
- 36.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?
- 37.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?
- 38.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 39.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 40.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
Answer key
- 715
- 649
- 473
- 286
- 770
- 759
- 1089
- 759
- 616
- 1012
- 605
- 869
- 583
- 550
- 638
- 913
- 143
- 198
- 825
- 418
- 902
- 737
- 693
- 506
- 671
- 913
- 726
- 1001
- 1111
- 748
- 638
- 451
- 671
- 781
- 561
- 319
- 979
- 528
- 946
- 1056
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