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): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
- 2.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 3.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 4.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 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.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?
- 7.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 8.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?
- 9.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 12.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 13.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 15.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 17.A leapfrog list starts 4, 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): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
- 19.A leapfrog list starts 9, 7 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): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
- 21.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?
- 22.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 23.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 24.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 26.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?
- 27.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 28.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 29.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
- 30.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
- 31.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 32.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 33.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?
- 34.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.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?
- 37.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
- 38.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?
- 39.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?
- 40.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
Answer key
- 550
- 781
- 880
- 847
- 308
- 594
- 1111
- 924
- 715
- 869
- 627
- 198
- 308
- 979
- 946
- 231
- 660
- 627
- 1111
- 1199
- 968
- 858
- 1056
- 583
- 396
- 913
- 660
- 671
- 946
- 1001
- 737
- 957
- 869
- 396
- 1122
- 649
- 715
- 814
- 363
- 715
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