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
- 1.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 2.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 3.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?
- 4.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 5.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?
- 6.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?
- 7.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 8.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 9.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 11.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 12.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 13.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 14.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
- 15.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 16.A leapfrog list starts 9, 9 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): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
- 18.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 20.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?
- 21.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 23.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?
- 24.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?
- 25.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 26.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?
- 27.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?
- 28.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?
- 29.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 30.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 31.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 32.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.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?
- 34.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 35.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 36.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 37.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.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?
- 39.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
Answer key
- 1023
- 286
- 693
- 341
- 341
- 143
- 1056
- 825
- 473
- 374
- 473
- 1067
- 363
- 528
- 847
- 1287
- 759
- 792
- 561
- 649
- 374
- 484
- 869
- 814
- 671
- 649
- 616
- 847
- 572
- 517
- 902
- 462
- 1034
- 803
- 231
- 462
- 583
- 924
- 231
- 726
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