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): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
- 2.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 3.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 5.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?
- 6.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 7.A leapfrog list starts 6, 7 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 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 10.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
- 11.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?
- 12.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
- 13.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 16.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 17.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?
- 18.A leapfrog list starts 6, 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): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
- 20.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 21.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 22.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 23.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?
- 24.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 25.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 26.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?
- 27.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?
- 28.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?
- 29.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?
- 30.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?
- 31.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 32.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 33.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?
- 34.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
- 35.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
- 36.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
- 37.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?
- 38.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 39.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?
- 40.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
Answer key
- 1199
- 693
- 737
- 418
- 1177
- 1122
- 946
- 429
- 561
- 253
- 1001
- 627
- 451
- 605
- 660
- 1232
- 528
- 418
- 660
- 594
- 550
- 902
- 539
- 253
- 308
- 726
- 616
- 473
- 484
- 968
- 374
- 649
- 363
- 682
- 1012
- 1023
- 616
- 836
- 649
- 231
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