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
- 1.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 2.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?
- 3.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 4.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?
- 5.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 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?
- 7.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 8.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 9.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?
- 10.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 11.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
- 12.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 13.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 14.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 15.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?
- 16.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?
- 17.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 18.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 20.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 21.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
- 22.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?
- 23.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 24.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?
- 25.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 26.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 27.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 28.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?
- 29.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 30.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?
- 31.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 32.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?
- 33.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?
- 34.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 35.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.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?
- 37.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 39.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 40.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 913
- 704
- 583
- 506
- 660
- 583
- 891
- 451
- 1089
- 1111
- 968
- 1001
- 495
- 231
- 726
- 231
- 253
- 814
- 649
- 1056
- 979
- 484
- 572
- 308
- 1089
- 946
- 902
- 1199
- 759
- 770
- 803
- 528
- 495
- 1177
- 1144
- 759
- 616
- 682
- 671
- 1177
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