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): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
- 2.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 3.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 4.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
- 5.A leapfrog list starts 8, 9 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): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
- 7.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?
- 8.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 9.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.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?
- 11.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
- 12.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 13.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
- 14.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 15.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 16.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
- 17.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 18.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 20.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?
- 21.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 22.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 23.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?
- 24.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
- 25.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 27.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?
- 28.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 29.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.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?
- 31.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?
- 32.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 33.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 34.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?
- 35.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 36.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 37.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?
- 38.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?
- 39.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 40.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 363
- 583
- 583
- 869
- 1232
- 792
- 418
- 1089
- 682
- 1232
- 1199
- 704
- 1001
- 858
- 627
- 539
- 143
- 583
- 363
- 759
- 308
- 396
- 1177
- 649
- 528
- 748
- 495
- 946
- 374
- 1067
- 429
- 231
- 1199
- 1144
- 924
- 638
- 484
- 671
- 506
- 363
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