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.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
- 3.A leapfrog list starts 6, 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): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. 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.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
- 7.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?
- 8.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 9.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 10.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.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?
- 12.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 13.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 14.A leapfrog list starts 3, 9 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 1, 7 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): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
- 17.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?
- 18.A leapfrog list starts 7, 6 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, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
- 21.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 22.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
- 23.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?
- 24.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 25.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 26.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 27.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?
- 28.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 29.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
- 30.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 31.A leapfrog list starts 3, 2 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 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 35.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 36.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 37.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?
- 38.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 39.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
- 40.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
Answer key
- 1023
- 924
- 858
- 429
- 253
- 671
- 869
- 605
- 550
- 539
- 814
- 231
- 1012
- 957
- 671
- 627
- 1287
- 913
- 968
- 880
- 803
- 583
- 484
- 682
- 407
- 935
- 792
- 286
- 737
- 396
- 341
- 1056
- 935
- 198
- 693
- 253
- 891
- 660
- 407
- 1111
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