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): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
- 2.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
- 3.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 5.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 6.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?
- 7.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 8.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 9.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 10.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?
- 11.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?
- 12.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 13.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?
- 14.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 15.A leapfrog list starts 6, 7 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 1, 4 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): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
- 18.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 19.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?
- 20.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 21.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 22.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?
- 23.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 25.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 26.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?
- 27.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 28.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 30.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 31.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?
- 32.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?
- 33.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 34.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.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?
- 37.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?
- 38.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 39.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?
- 40.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
Answer key
- 759
- 1034
- 1089
- 506
- 484
- 671
- 616
- 847
- 1023
- 429
- 858
- 605
- 869
- 759
- 946
- 407
- 704
- 1199
- 363
- 880
- 902
- 572
- 847
- 198
- 396
- 605
- 781
- 528
- 638
- 231
- 308
- 748
- 979
- 1232
- 924
- 869
- 253
- 759
- 627
- 913
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