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
- 1.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 2.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 3.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
- 4.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?
- 5.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 6.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 7.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?
- 8.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 9.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?
- 10.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 12.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
- 13.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 14.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 15.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
- 17.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?
- 18.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?
- 19.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 20.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?
- 21.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?
- 22.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 23.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 25.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?
- 26.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?
- 27.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 28.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 29.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 30.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?
- 31.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 34.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 35.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
- 36.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?
- 37.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 39.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 40.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 847
- 143
- 913
- 968
- 704
- 748
- 341
- 1001
- 506
- 715
- 913
- 924
- 902
- 550
- 957
- 770
- 462
- 473
- 1144
- 792
- 847
- 737
- 1056
- 638
- 407
- 968
- 660
- 451
- 363
- 319
- 836
- 561
- 451
- 671
- 363
- 550
- 396
- 627
- 319
- 198
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