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 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 3.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 4.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?
- 5.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 6.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?
- 7.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 8.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 9.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 10.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
- 11.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 12.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?
- 13.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 15.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 16.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 17.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 18.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?
- 19.A leapfrog list starts 1, 7 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 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.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?
- 22.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 23.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?
- 24.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?
- 25.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.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?
- 27.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
- 28.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 31.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 32.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 33.A leapfrog list starts 8, 8 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): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 35.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?
- 36.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 37.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
- 38.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?
- 39.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 40.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?
Answer key
- 583
- 363
- 605
- 825
- 374
- 880
- 1056
- 682
- 605
- 891
- 704
- 880
- 1122
- 935
- 286
- 1012
- 484
- 506
- 671
- 528
- 1232
- 308
- 594
- 517
- 341
- 374
- 836
- 594
- 429
- 396
- 1232
- 407
- 1144
- 341
- 143
- 451
- 429
- 770
- 847
- 1089
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