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 1, 3 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): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 3.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?
- 4.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?
- 5.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 8.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
- 9.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?
- 10.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 11.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
- 12.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 13.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?
- 14.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 16.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?
- 17.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 18.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
- 19.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 22.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 23.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 25.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 26.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 27.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
- 28.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?
- 29.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?
- 30.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 32.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
- 33.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.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?
- 35.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?
- 36.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?
- 37.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 38.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 39.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 40.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
Answer key
- 319
- 143
- 1177
- 814
- 506
- 407
- 231
- 1089
- 341
- 847
- 198
- 1232
- 1056
- 880
- 286
- 1122
- 869
- 858
- 649
- 550
- 671
- 891
- 671
- 528
- 550
- 1034
- 693
- 594
- 671
- 231
- 451
- 572
- 792
- 495
- 1199
- 396
- 1177
- 1001
- 462
- 583
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