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
- 1.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 2.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?
- 3.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?
- 4.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 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?
- 6.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 7.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?
- 8.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 9.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?
- 10.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 11.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?
- 12.A leapfrog list starts 8, 3 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, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 15.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?
- 16.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?
- 17.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 18.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 19.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 20.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?
- 21.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 22.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 23.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?
- 24.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?
- 25.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?
- 26.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 27.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?
- 28.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 29.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 30.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
- 31.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.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?
- 34.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.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?
- 36.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?
- 37.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 39.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 40.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?
Answer key
- 671
- 286
- 649
- 396
- 308
- 341
- 671
- 1287
- 1287
- 781
- 583
- 704
- 506
- 627
- 594
- 682
- 869
- 880
- 726
- 1177
- 770
- 1012
- 803
- 418
- 253
- 363
- 231
- 847
- 814
- 1111
- 363
- 198
- 759
- 891
- 693
- 814
- 1001
- 1001
- 1122
- 616
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