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
- 1.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 2.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
- 3.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 4.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 5.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 6.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?
- 7.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.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?
- 9.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 10.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?
- 11.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 12.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 13.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 14.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 15.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?
- 16.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 17.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 18.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?
- 19.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 20.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?
- 21.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
- 22.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
- 23.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
- 24.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?
- 25.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 26.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 27.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 28.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 29.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 30.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
- 31.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?
- 32.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?
- 33.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?
- 34.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 35.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 36.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?
- 37.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?
- 38.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 39.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?
- 40.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 143
- 1089
- 341
- 649
- 770
- 583
- 1122
- 231
- 946
- 825
- 583
- 473
- 759
- 594
- 957
- 286
- 1067
- 594
- 891
- 803
- 693
- 1111
- 594
- 770
- 682
- 1111
- 737
- 1177
- 913
- 759
- 1177
- 341
- 1144
- 495
- 517
- 814
- 473
- 484
- 924
- 473
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