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, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
- 2.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 3.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 4.A leapfrog list starts 5, 8 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): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
- 6.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?
- 7.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 8.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?
- 9.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 10.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 11.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 12.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?
- 13.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 14.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?
- 15.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?
- 16.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 17.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?
- 18.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?
- 19.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?
- 20.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.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?
- 22.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?
- 23.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 24.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?
- 25.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 27.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 28.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 29.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 30.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 31.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 32.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 33.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?
- 34.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?
- 35.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
- 36.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?
- 37.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 38.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?
- 39.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 40.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
Answer key
- 616
- 803
- 407
- 979
- 1199
- 682
- 1199
- 814
- 1034
- 715
- 836
- 693
- 484
- 594
- 1199
- 671
- 605
- 198
- 1144
- 737
- 528
- 638
- 308
- 1111
- 814
- 528
- 880
- 495
- 1287
- 902
- 429
- 638
- 198
- 484
- 869
- 308
- 957
- 660
- 726
- 572
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