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 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 3.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 4.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?
- 5.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 6.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?
- 7.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
- 8.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 10.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 11.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?
- 12.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 13.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.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?
- 15.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?
- 16.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?
- 17.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 20.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?
- 21.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?
- 22.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?
- 23.A leapfrog list starts 9, 5 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): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
- 25.A leapfrog list starts 2, 3 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): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 27.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?
- 28.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
- 29.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 30.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?
- 31.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 32.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 33.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
- 34.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?
- 35.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 36.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?
- 37.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 38.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?
- 39.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 40.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
Answer key
- 143
- 1111
- 550
- 715
- 869
- 1001
- 407
- 814
- 1111
- 319
- 814
- 286
- 363
- 418
- 649
- 704
- 253
- 847
- 198
- 1056
- 759
- 605
- 935
- 770
- 374
- 759
- 869
- 825
- 748
- 198
- 374
- 902
- 550
- 528
- 704
- 858
- 1199
- 627
- 759
- 858
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