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 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 2.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 3.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?
- 4.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?
- 5.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 6.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?
- 7.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 8.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 9.A leapfrog list starts 6, 8 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): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
- 11.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 12.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 13.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?
- 14.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?
- 15.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
- 16.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?
- 17.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 18.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?
- 19.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
- 20.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 21.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
- 22.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 23.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 24.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
- 25.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 27.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?
- 28.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?
- 29.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 31.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?
- 32.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 33.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 35.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?
- 36.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 37.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 38.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?
- 39.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?
- 40.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
Answer key
- 1001
- 1089
- 143
- 1232
- 638
- 473
- 968
- 858
- 1034
- 792
- 781
- 484
- 583
- 363
- 594
- 660
- 550
- 748
- 737
- 517
- 506
- 1012
- 979
- 693
- 649
- 1067
- 341
- 407
- 319
- 374
- 616
- 847
- 979
- 506
- 902
- 847
- 561
- 726
- 253
- 759
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