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, 4 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): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
- 3.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
- 4.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?
- 5.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?
- 6.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?
- 7.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?
- 8.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 9.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?
- 10.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 11.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?
- 12.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 14.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?
- 15.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?
- 16.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 17.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 18.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 20.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
- 21.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 22.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 23.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?
- 24.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 25.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?
- 26.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 27.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 29.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?
- 30.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 31.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 33.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 34.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?
- 35.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
- 36.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 37.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 38.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 39.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?
- 40.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
Answer key
- 462
- 715
- 957
- 407
- 1111
- 1056
- 649
- 407
- 638
- 935
- 473
- 836
- 792
- 814
- 462
- 704
- 1034
- 528
- 858
- 770
- 550
- 836
- 341
- 572
- 506
- 759
- 1089
- 253
- 517
- 308
- 1111
- 1232
- 286
- 847
- 308
- 924
- 561
- 451
- 1012
- 891
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