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): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
- 2.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 3.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 4.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?
- 5.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?
- 6.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 8.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 10.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?
- 11.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?
- 12.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 13.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 14.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
- 16.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 17.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 18.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 19.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
- 20.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 21.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 22.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 23.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 24.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 25.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 26.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 27.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
- 28.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 29.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 30.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?
- 31.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
- 32.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 33.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
- 34.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.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?
- 37.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?
- 38.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?
- 39.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?
- 40.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
Answer key
- 1232
- 143
- 451
- 286
- 308
- 1034
- 506
- 484
- 649
- 847
- 462
- 1023
- 1034
- 1199
- 583
- 286
- 1056
- 715
- 616
- 583
- 583
- 396
- 704
- 781
- 880
- 308
- 737
- 836
- 495
- 583
- 627
- 1001
- 605
- 539
- 638
- 374
- 638
- 649
- 1144
- 770
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