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
- 1.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 2.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 3.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?
- 4.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 5.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 6.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 7.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?
- 8.A leapfrog list starts 3, 6 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 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
- 11.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
- 12.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?
- 13.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 14.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?
- 15.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 16.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?
- 17.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?
- 18.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 19.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 20.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 21.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 22.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?
- 23.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?
- 24.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 25.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?
- 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 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 29.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 30.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
- 31.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 32.A leapfrog list starts 4, 2 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 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 35.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 36.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 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.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
- 39.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?
- 40.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
Answer key
- 473
- 198
- 528
- 704
- 572
- 913
- 759
- 693
- 726
- 418
- 715
- 858
- 946
- 605
- 814
- 803
- 286
- 550
- 374
- 792
- 484
- 616
- 616
- 847
- 451
- 770
- 1177
- 748
- 462
- 583
- 528
- 396
- 869
- 693
- 561
- 671
- 759
- 946
- 902
- 517
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