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 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
- 3.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 4.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 5.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 6.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 7.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 8.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.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?
- 10.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?
- 11.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 12.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?
- 13.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 15.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 16.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 17.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
- 18.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?
- 19.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
- 20.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 21.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 22.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?
- 23.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 24.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?
- 25.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 26.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?
- 27.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?
- 28.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?
- 29.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
- 30.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 31.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?
- 32.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?
- 33.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 34.A leapfrog list starts 2, 4 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 9, 5 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): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 37.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?
- 38.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 39.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
- 40.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
Answer key
- 286
- 825
- 704
- 572
- 462
- 1232
- 473
- 1023
- 671
- 1012
- 583
- 1177
- 396
- 847
- 407
- 1177
- 1287
- 913
- 946
- 1023
- 143
- 363
- 869
- 968
- 341
- 1023
- 308
- 880
- 1056
- 1067
- 374
- 1232
- 1001
- 462
- 935
- 231
- 583
- 803
- 407
- 495
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