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): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
- 2.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?
- 3.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?
- 4.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?
- 5.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?
- 6.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
- 8.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 9.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 10.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?
- 11.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?
- 12.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
- 13.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?
- 14.A leapfrog list starts 1, 5 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 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 17.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
- 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 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 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, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
- 23.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?
- 24.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?
- 25.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 26.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 27.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?
- 28.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 29.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 30.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.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?
- 32.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 33.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 34.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 35.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
- 36.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 37.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 38.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 39.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
- 40.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
Answer key
- 660
- 781
- 396
- 902
- 407
- 429
- 1177
- 814
- 253
- 814
- 1111
- 869
- 429
- 495
- 363
- 726
- 1177
- 594
- 341
- 451
- 803
- 671
- 231
- 957
- 891
- 528
- 836
- 759
- 231
- 1001
- 715
- 198
- 517
- 506
- 374
- 660
- 836
- 1067
- 803
- 572
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