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
- 1.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 2.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 3.A leapfrog list starts 5, 6 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): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
- 5.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?
- 6.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 7.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.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?
- 9.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 10.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 11.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?
- 12.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 13.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 14.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 15.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 16.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 17.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?
- 18.A leapfrog list starts 7, 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 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 21.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 22.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 23.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
- 24.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 25.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 26.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?
- 27.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
- 29.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?
- 30.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?
- 31.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?
- 32.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?
- 33.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?
- 34.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
- 35.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?
- 36.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?
- 37.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?
- 38.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
- 39.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 40.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?
Answer key
- 1023
- 770
- 803
- 726
- 253
- 198
- 902
- 1122
- 1001
- 693
- 1056
- 396
- 550
- 781
- 913
- 1287
- 847
- 561
- 1232
- 1034
- 825
- 1177
- 660
- 528
- 616
- 495
- 308
- 1144
- 671
- 605
- 374
- 957
- 1232
- 759
- 495
- 407
- 319
- 517
- 462
- 638
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