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): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
- 2.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?
- 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?
- 4.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 5.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 6.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 7.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 8.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 9.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?
- 10.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?
- 11.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 12.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?
- 13.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?
- 14.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?
- 15.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?
- 16.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 17.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 18.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
- 19.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 20.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 21.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
- 22.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 23.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?
- 24.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
- 25.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?
- 26.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?
- 27.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.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?
- 29.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
- 30.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 31.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 32.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 33.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 34.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?
- 35.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 36.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?
- 37.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
- 39.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
- 40.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
Answer key
- 957
- 341
- 1177
- 429
- 418
- 814
- 473
- 649
- 1122
- 792
- 748
- 396
- 143
- 638
- 693
- 1111
- 231
- 682
- 198
- 847
- 363
- 1287
- 759
- 913
- 495
- 198
- 418
- 638
- 286
- 374
- 341
- 891
- 1001
- 858
- 495
- 253
- 781
- 792
- 1287
- 968
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