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): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
- 2.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 3.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 4.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?
- 5.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 6.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 7.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 9.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?
- 10.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
- 11.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 12.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
- 13.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 14.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?
- 15.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
- 16.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 17.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 18.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?
- 19.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?
- 20.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 21.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?
- 22.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
- 23.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?
- 24.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 25.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?
- 26.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?
- 27.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 29.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 31.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 32.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?
- 33.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 34.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
- 35.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 36.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 38.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 39.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 40.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
Answer key
- 484
- 1034
- 583
- 473
- 638
- 550
- 660
- 407
- 396
- 1023
- 902
- 572
- 1111
- 935
- 726
- 748
- 770
- 341
- 814
- 539
- 506
- 363
- 704
- 825
- 286
- 902
- 429
- 968
- 341
- 319
- 495
- 550
- 759
- 583
- 572
- 748
- 726
- 528
- 704
- 341
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