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): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
- 2.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 3.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 4.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?
- 5.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 6.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 9.A leapfrog list starts 2, 7 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): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
- 11.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?
- 12.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?
- 13.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?
- 14.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?
- 15.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 16.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 17.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?
- 18.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?
- 19.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?
- 20.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
- 21.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 22.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 23.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
- 24.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 25.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?
- 26.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 27.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
- 28.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
- 29.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?
- 30.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 31.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 32.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 33.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
- 34.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?
- 35.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
- 36.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 37.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?
- 38.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?
- 39.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?
- 40.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
Answer key
- 594
- 286
- 847
- 913
- 451
- 814
- 913
- 759
- 726
- 847
- 627
- 253
- 1232
- 825
- 418
- 528
- 286
- 726
- 847
- 1111
- 759
- 484
- 638
- 473
- 143
- 231
- 506
- 814
- 1199
- 374
- 341
- 660
- 968
- 495
- 319
- 1023
- 1023
- 682
- 869
- 792
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