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
- 1.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 2.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 3.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?
- 4.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?
- 5.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 6.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
- 7.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.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?
- 9.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 10.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 11.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?
- 12.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 13.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?
- 14.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 15.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?
- 16.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 17.A leapfrog list starts 8, 6 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 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 20.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 21.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 22.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 23.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
- 24.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
- 25.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?
- 26.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 27.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.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?
- 29.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 30.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
- 31.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?
- 32.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 33.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 34.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 35.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 36.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 37.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 38.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.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?
- 40.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
Answer key
- 814
- 1177
- 869
- 407
- 616
- 561
- 1023
- 759
- 726
- 803
- 506
- 429
- 814
- 1089
- 781
- 198
- 968
- 583
- 704
- 528
- 770
- 1012
- 968
- 803
- 649
- 891
- 550
- 319
- 341
- 682
- 616
- 583
- 682
- 1144
- 561
- 1067
- 231
- 1177
- 715
- 847
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