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.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 3.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 4.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
- 5.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?
- 6.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 7.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 9.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 10.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 11.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
- 12.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 13.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?
- 14.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?
- 15.A leapfrog list starts 9, 8 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 4, 6 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 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.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?
- 19.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?
- 20.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 22.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?
- 23.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 24.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 25.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?
- 26.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?
- 27.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
- 28.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?
- 29.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 30.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?
- 31.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?
- 32.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 33.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 34.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
- 35.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.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?
- 37.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?
- 38.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?
- 39.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
- 40.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
Answer key
- 605
- 814
- 253
- 814
- 231
- 1232
- 341
- 759
- 880
- 869
- 319
- 308
- 792
- 1001
- 1199
- 748
- 836
- 429
- 473
- 693
- 693
- 704
- 847
- 495
- 726
- 1067
- 913
- 803
- 583
- 506
- 1232
- 1111
- 627
- 935
- 517
- 484
- 715
- 671
- 495
- 407
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