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
- 1.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 2.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?
- 3.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 4.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 5.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
- 6.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?
- 7.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?
- 8.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?
- 9.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 10.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 11.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 12.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?
- 13.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 14.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 15.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 16.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?
- 17.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?
- 18.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 19.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?
- 20.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?
- 21.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?
- 22.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?
- 23.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 24.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?
- 25.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?
- 26.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 27.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 28.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?
- 29.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?
- 30.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 31.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 32.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?
- 33.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 34.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?
- 35.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?
- 36.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?
- 37.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
- 38.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
- 39.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?
- 40.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
Answer key
- 781
- 1067
- 363
- 143
- 418
- 902
- 957
- 253
- 231
- 902
- 539
- 957
- 847
- 429
- 847
- 616
- 847
- 231
- 913
- 880
- 429
- 803
- 253
- 1287
- 1287
- 495
- 583
- 627
- 946
- 286
- 1111
- 1177
- 737
- 1001
- 528
- 671
- 891
- 770
- 748
- 1067
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