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
- 1.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 2.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 3.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
- 4.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 5.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?
- 6.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
- 7.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 8.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?
- 9.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 10.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
- 11.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?
- 12.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?
- 13.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 14.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?
- 15.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 17.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?
- 18.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?
- 19.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?
- 20.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 21.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 22.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 23.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 24.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?
- 25.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?
- 26.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 27.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 28.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 29.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
- 30.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 32.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?
- 33.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?
- 34.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 35.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 36.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?
- 37.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 38.A leapfrog list starts 9, 1 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 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.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?
Answer key
- 319
- 363
- 561
- 616
- 308
- 935
- 583
- 638
- 726
- 528
- 583
- 473
- 1034
- 869
- 407
- 583
- 308
- 902
- 924
- 836
- 396
- 308
- 462
- 1023
- 792
- 693
- 506
- 517
- 759
- 561
- 495
- 671
- 1067
- 429
- 627
- 913
- 902
- 583
- 682
- 814
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