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): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 2.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 3.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?
- 4.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?
- 5.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?
- 6.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?
- 7.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 8.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 9.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 10.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 11.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 12.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 13.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 15.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 16.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 17.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 18.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?
- 19.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?
- 20.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 21.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 22.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?
- 23.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
- 24.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?
- 25.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 27.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 28.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 29.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 30.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 31.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?
- 32.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 33.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?
- 34.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?
- 35.A leapfrog list starts 2, 2 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): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
- 37.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?
- 38.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 39.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 40.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
Answer key
- 341
- 517
- 495
- 418
- 484
- 231
- 792
- 143
- 825
- 671
- 319
- 616
- 671
- 308
- 759
- 495
- 550
- 253
- 792
- 671
- 946
- 759
- 605
- 1122
- 484
- 968
- 583
- 418
- 847
- 1122
- 759
- 561
- 880
- 770
- 286
- 561
- 913
- 583
- 781
- 869
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