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 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.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?
- 3.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
- 4.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 5.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?
- 6.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?
- 7.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 8.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
- 9.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?
- 10.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 11.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?
- 12.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 13.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 14.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 15.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 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?
- 17.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 18.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 19.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?
- 20.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 21.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 22.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 23.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 24.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 25.A leapfrog list starts 7, 4 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, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
- 27.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?
- 28.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?
- 29.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 30.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?
- 31.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 32.A leapfrog list starts 4, 1 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 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 35.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 36.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 37.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?
- 38.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?
- 39.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 40.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?
Answer key
- 583
- 473
- 1001
- 286
- 671
- 759
- 902
- 671
- 825
- 286
- 935
- 627
- 418
- 1034
- 462
- 803
- 649
- 759
- 869
- 946
- 1001
- 484
- 506
- 869
- 737
- 803
- 671
- 198
- 759
- 341
- 231
- 308
- 1056
- 847
- 583
- 462
- 605
- 671
- 1177
- 627
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