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
- 1.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 2.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?
- 3.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 4.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?
- 5.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 6.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?
- 7.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 8.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 9.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 10.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 11.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
- 12.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 14.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 15.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.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?
- 17.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
- 18.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?
- 19.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 21.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?
- 22.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 23.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 24.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 25.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?
- 26.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 27.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 28.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 29.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?
- 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): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
- 32.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 33.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 34.A leapfrog list starts 8, 5 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): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
- 36.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?
- 37.A leapfrog list starts 4, 4 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): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
- 39.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
- 40.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 418
- 627
- 649
- 253
- 616
- 737
- 979
- 836
- 1111
- 726
- 1067
- 616
- 231
- 968
- 693
- 231
- 473
- 594
- 1067
- 528
- 803
- 671
- 253
- 759
- 847
- 1089
- 594
- 957
- 1177
- 605
- 1122
- 286
- 341
- 880
- 1023
- 814
- 572
- 726
- 902
- 550
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