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 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 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?
- 3.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 4.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 5.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 6.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 8.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 9.A leapfrog list starts 1, 5 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 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 12.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 13.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 14.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 15.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?
- 16.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?
- 17.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
- 18.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 19.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 20.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?
- 21.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
- 22.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 23.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
- 24.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?
- 25.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
- 26.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 27.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 28.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?
- 29.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
- 30.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?
- 31.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
- 32.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?
- 33.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?
- 34.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 35.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 36.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?
- 37.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 38.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 40.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
Answer key
- 462
- 319
- 715
- 1034
- 737
- 572
- 726
- 627
- 495
- 913
- 627
- 671
- 319
- 1122
- 649
- 1122
- 726
- 198
- 957
- 781
- 957
- 429
- 979
- 550
- 880
- 550
- 858
- 1034
- 1111
- 715
- 583
- 649
- 616
- 792
- 748
- 803
- 891
- 286
- 528
- 418
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