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 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 2.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?
- 3.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?
- 4.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
- 5.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 7.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?
- 8.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 9.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?
- 10.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
- 11.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?
- 12.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 13.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 14.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?
- 15.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.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?
- 17.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?
- 18.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
- 19.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 20.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 22.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 23.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 24.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?
- 25.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 26.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?
- 27.A leapfrog list starts 8, 5 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 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 30.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
- 31.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 32.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 33.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 34.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
- 35.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 36.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?
- 37.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?
- 38.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?
- 39.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
- 40.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
Answer key
- 1089
- 319
- 319
- 1144
- 517
- 847
- 1056
- 1122
- 528
- 550
- 198
- 495
- 341
- 638
- 803
- 374
- 649
- 1287
- 671
- 1089
- 803
- 429
- 1012
- 792
- 759
- 847
- 880
- 858
- 286
- 935
- 561
- 528
- 308
- 1023
- 891
- 924
- 781
- 913
- 484
- 836
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