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
- 1.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 2.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?
- 3.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 5.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 6.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?
- 7.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?
- 8.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 9.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?
- 10.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 11.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?
- 12.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 13.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 16.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
- 17.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 18.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 19.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
- 20.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 21.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 22.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 23.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 24.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 25.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 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.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 28.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?
- 29.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?
- 30.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 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?
- 32.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 33.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?
- 34.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?
- 35.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?
- 36.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?
- 37.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 38.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?
- 39.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?
- 40.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
Answer key
- 726
- 286
- 528
- 847
- 451
- 649
- 902
- 1001
- 594
- 935
- 825
- 286
- 550
- 770
- 484
- 627
- 638
- 671
- 473
- 792
- 1056
- 506
- 748
- 649
- 1199
- 539
- 143
- 891
- 704
- 869
- 781
- 1012
- 682
- 781
- 616
- 319
- 759
- 407
- 1056
- 429
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