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.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 3.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 4.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?
- 5.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 7.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 9.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 10.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 11.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 12.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 13.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 14.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.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?
- 16.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?
- 17.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?
- 18.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 19.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 20.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?
- 21.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?
- 22.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 23.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 24.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
- 25.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 26.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 27.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?
- 28.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 29.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.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?
- 31.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?
- 32.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?
- 33.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
- 34.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.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?
- 36.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?
- 37.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?
- 38.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 39.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 40.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 561
- 1089
- 748
- 528
- 715
- 616
- 627
- 693
- 649
- 506
- 583
- 396
- 418
- 506
- 869
- 231
- 1232
- 605
- 286
- 902
- 341
- 517
- 583
- 583
- 451
- 803
- 143
- 231
- 407
- 1232
- 605
- 363
- 198
- 935
- 473
- 616
- 1001
- 1012
- 495
- 319
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