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
- 1.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 2.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 3.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 4.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 5.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?
- 6.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
- 7.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 8.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?
- 9.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?
- 10.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 11.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?
- 12.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
- 13.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 14.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?
- 15.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
- 16.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
- 17.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 18.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 20.A leapfrog list starts 9, 9 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 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 22.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
- 23.A leapfrog list starts 5, 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): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
- 25.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 26.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
- 27.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?
- 28.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 29.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?
- 30.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 32.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?
- 33.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?
- 34.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
- 35.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
- 36.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
- 37.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 38.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 39.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?
- 40.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
Answer key
- 1232
- 715
- 660
- 231
- 715
- 627
- 968
- 759
- 792
- 583
- 429
- 946
- 1067
- 286
- 1144
- 825
- 946
- 1067
- 462
- 1287
- 253
- 847
- 539
- 1034
- 429
- 792
- 506
- 726
- 319
- 1001
- 869
- 737
- 1177
- 748
- 803
- 583
- 847
- 484
- 627
- 704
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