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
- 1.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 2.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 3.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?
- 4.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?
- 5.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?
- 6.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?
- 7.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?
- 8.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?
- 9.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?
- 10.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 11.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?
- 12.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
- 13.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 14.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?
- 15.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 16.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 17.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 18.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 19.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 20.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 22.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
- 23.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 24.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 25.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 26.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 27.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.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?
- 29.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
- 30.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 31.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 32.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
- 33.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?
- 34.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?
- 35.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 36.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 37.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?
- 38.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 39.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?
- 40.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
Answer key
- 693
- 1199
- 902
- 473
- 407
- 1177
- 550
- 143
- 649
- 583
- 792
- 1067
- 704
- 715
- 1111
- 847
- 814
- 627
- 759
- 506
- 847
- 968
- 781
- 517
- 396
- 407
- 451
- 814
- 594
- 957
- 1012
- 979
- 671
- 781
- 363
- 572
- 704
- 451
- 495
- 539
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