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 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 3.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?
- 4.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
- 5.A leapfrog list starts 8, 8 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): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
- 7.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
- 8.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 9.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 11.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 12.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 13.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?
- 14.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 15.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 16.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
- 17.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 19.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?
- 20.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
- 21.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
- 22.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?
- 23.A leapfrog list starts 1, 9 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 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 26.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 27.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 28.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 29.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 30.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 31.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 32.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
- 33.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 34.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
- 35.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?
- 36.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 37.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 38.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 39.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 40.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 649
- 572
- 781
- 418
- 1144
- 605
- 858
- 759
- 759
- 803
- 253
- 363
- 858
- 143
- 638
- 286
- 902
- 506
- 528
- 1232
- 693
- 550
- 847
- 143
- 847
- 671
- 847
- 396
- 891
- 693
- 286
- 1287
- 539
- 572
- 407
- 737
- 451
- 748
- 1111
- 1232
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