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.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?
- 2.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?
- 3.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 4.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?
- 5.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 6.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 7.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?
- 8.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 9.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?
- 10.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?
- 11.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 12.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?
- 13.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?
- 14.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 15.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 16.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?
- 17.A leapfrog list starts 8, 9 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): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
- 19.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.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?
- 21.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?
- 22.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?
- 23.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 25.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 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?
- 27.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 28.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?
- 29.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 30.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 31.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?
- 32.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?
- 33.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 34.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?
- 35.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 36.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 37.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?
- 38.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?
- 39.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 40.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
Answer key
- 550
- 649
- 473
- 253
- 902
- 319
- 836
- 594
- 715
- 847
- 979
- 638
- 143
- 649
- 726
- 726
- 1232
- 539
- 451
- 759
- 319
- 231
- 891
- 737
- 902
- 649
- 847
- 825
- 792
- 759
- 1034
- 715
- 759
- 726
- 308
- 891
- 792
- 847
- 1111
- 660
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