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
- 1.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 2.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?
- 3.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 4.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 5.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
- 6.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
- 7.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 8.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 9.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 10.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 12.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
- 14.A leapfrog list starts 3, 7 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): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 16.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 17.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
- 18.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 19.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?
- 20.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?
- 21.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
- 22.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 23.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?
- 24.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 25.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?
- 26.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?
- 27.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 28.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?
- 29.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
- 30.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 32.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
- 33.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 35.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 36.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 37.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 38.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 39.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
Answer key
- 682
- 726
- 561
- 396
- 638
- 1122
- 803
- 770
- 979
- 1144
- 231
- 682
- 319
- 781
- 759
- 319
- 616
- 638
- 1034
- 737
- 198
- 572
- 847
- 1287
- 814
- 616
- 968
- 583
- 308
- 913
- 407
- 374
- 693
- 605
- 308
- 781
- 946
- 781
- 1122
- 627
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