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?
- 2.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 3.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?
- 4.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 5.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
- 6.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 7.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
- 8.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 9.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
- 10.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 11.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?
- 12.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?
- 13.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.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?
- 15.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?
- 16.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?
- 17.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 18.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 19.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?
- 20.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?
- 21.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 22.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 23.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?
- 24.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?
- 25.A leapfrog list starts 1, 4 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): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
- 27.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?
- 28.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?
- 29.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
- 30.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 31.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 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?
- 33.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 34.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?
- 35.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
- 36.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?
- 37.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 38.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.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?
- 40.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 550
- 704
- 979
- 308
- 429
- 462
- 704
- 638
- 286
- 594
- 924
- 913
- 506
- 451
- 682
- 671
- 660
- 363
- 924
- 473
- 605
- 869
- 1023
- 957
- 407
- 1287
- 539
- 957
- 1232
- 1111
- 429
- 649
- 924
- 1067
- 616
- 231
- 143
- 1111
- 451
- 671
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