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.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?
- 2.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 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?
- 4.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 5.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 6.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 7.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 8.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.A leapfrog list starts 3, 1 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, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
- 12.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 13.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?
- 14.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 15.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 16.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 17.A leapfrog list starts 7, 5 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): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
- 19.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 20.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 21.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 23.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?
- 24.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?
- 25.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 26.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
- 27.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
- 28.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?
- 29.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.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?
- 31.A leapfrog list starts 1, 9 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 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 34.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.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?
- 36.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?
- 37.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?
- 38.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
- 39.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?
- 40.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
Answer key
- 781
- 693
- 869
- 715
- 473
- 1056
- 616
- 671
- 253
- 473
- 473
- 396
- 792
- 1067
- 913
- 792
- 825
- 198
- 1034
- 561
- 726
- 649
- 319
- 649
- 1144
- 506
- 253
- 583
- 1144
- 572
- 847
- 396
- 418
- 759
- 979
- 726
- 715
- 1177
- 715
- 671
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