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.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?
- 2.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 3.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 4.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?
- 5.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?
- 6.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 7.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 8.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.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?
- 10.A leapfrog list starts 1, 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): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
- 12.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?
- 13.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?
- 14.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 16.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 17.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 18.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 19.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?
- 20.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?
- 21.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 22.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?
- 23.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 24.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 25.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
- 26.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
- 27.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?
- 28.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?
- 29.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 30.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 31.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?
- 32.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?
- 33.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 34.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?
- 35.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 37.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?
- 38.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?
- 39.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 40.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
Answer key
- 308
- 506
- 517
- 1287
- 198
- 253
- 671
- 1023
- 1177
- 319
- 891
- 682
- 1067
- 462
- 671
- 550
- 418
- 792
- 704
- 341
- 198
- 616
- 781
- 583
- 1056
- 704
- 803
- 660
- 616
- 1034
- 660
- 836
- 1023
- 913
- 231
- 737
- 363
- 858
- 605
- 231
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