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, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
- 2.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?
- 3.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 4.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 5.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 6.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?
- 7.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 8.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
- 9.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 10.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 11.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 12.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?
- 13.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
- 14.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 15.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
- 16.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 17.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 18.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?
- 19.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 20.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?
- 21.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
- 22.A leapfrog list starts 8, 1 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): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
- 24.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?
- 25.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
- 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.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
- 29.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?
- 30.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 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 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 35.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 36.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 37.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
- 38.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 39.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?
- 40.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
Answer key
- 638
- 825
- 374
- 858
- 462
- 836
- 1001
- 660
- 847
- 968
- 539
- 418
- 583
- 583
- 528
- 781
- 528
- 341
- 1287
- 583
- 880
- 528
- 484
- 429
- 561
- 792
- 308
- 902
- 649
- 759
- 847
- 594
- 583
- 792
- 880
- 671
- 1012
- 649
- 1111
- 308
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