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): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
- 2.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
- 3.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?
- 4.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?
- 5.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 6.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 7.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 8.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?
- 9.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 10.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 12.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?
- 13.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 14.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?
- 15.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 16.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
- 17.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 18.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 19.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 20.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 21.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 22.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 23.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?
- 24.A leapfrog list starts 2, 6 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 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.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?
- 27.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.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?
- 29.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 30.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 31.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
- 32.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?
- 33.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 35.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 36.A leapfrog list starts 9, 2 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 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 39.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 40.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?
Answer key
- 616
- 748
- 671
- 341
- 616
- 869
- 770
- 649
- 374
- 891
- 924
- 374
- 561
- 704
- 143
- 924
- 891
- 649
- 418
- 1144
- 913
- 968
- 198
- 638
- 715
- 770
- 1144
- 825
- 550
- 1067
- 814
- 902
- 583
- 902
- 627
- 671
- 506
- 539
- 836
- 561
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