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
- 1.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 2.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?
- 3.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
- 4.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?
- 5.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 6.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?
- 7.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 8.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 9.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?
- 10.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
- 11.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?
- 12.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 14.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?
- 15.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?
- 16.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 17.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 19.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 20.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?
- 21.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 22.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
- 23.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 24.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?
- 25.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 26.A leapfrog list starts 2, 3 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 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 28.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 29.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 30.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 31.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 32.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 33.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 34.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 35.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?
- 36.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 37.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 38.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?
- 39.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 40.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 792
- 902
- 1034
- 1067
- 363
- 704
- 396
- 506
- 451
- 1089
- 231
- 880
- 814
- 858
- 1287
- 825
- 935
- 759
- 407
- 616
- 649
- 748
- 583
- 374
- 660
- 374
- 803
- 902
- 594
- 1056
- 616
- 759
- 1012
- 583
- 891
- 1089
- 528
- 1177
- 517
- 924
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