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): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
- 2.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 3.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 4.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?
- 5.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?
- 6.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 7.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 8.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
- 9.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?
- 10.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 11.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
- 12.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 13.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 14.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.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?
- 16.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 17.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?
- 18.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?
- 19.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 20.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?
- 21.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 22.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?
- 23.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?
- 24.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
- 25.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?
- 26.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?
- 27.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 29.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 30.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?
- 31.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 32.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?
- 33.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 35.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?
- 36.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 37.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 38.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?
- 39.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?
- 40.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
Answer key
- 286
- 902
- 572
- 583
- 1023
- 308
- 484
- 748
- 880
- 1232
- 1122
- 1067
- 759
- 143
- 363
- 803
- 660
- 847
- 396
- 561
- 462
- 946
- 715
- 374
- 539
- 1177
- 847
- 517
- 847
- 649
- 616
- 902
- 495
- 594
- 495
- 627
- 693
- 473
- 462
- 1056
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