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 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 2.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 3.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 4.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?
- 5.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?
- 6.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 7.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?
- 8.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?
- 9.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?
- 10.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 12.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?
- 13.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 14.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?
- 15.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
- 16.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?
- 17.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 18.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?
- 19.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
- 20.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?
- 21.A leapfrog list starts 6, 4 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 6, 6 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): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
- 24.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 25.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 26.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 27.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?
- 28.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.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?
- 30.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 31.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 32.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 33.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?
- 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.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?
- 36.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 37.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
- 38.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.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?
- 40.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
Answer key
- 495
- 253
- 473
- 550
- 1034
- 638
- 539
- 429
- 451
- 869
- 462
- 583
- 517
- 924
- 671
- 561
- 594
- 1177
- 1067
- 374
- 682
- 858
- 594
- 231
- 616
- 737
- 649
- 704
- 253
- 781
- 759
- 1001
- 253
- 726
- 341
- 308
- 737
- 418
- 957
- 1056
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