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 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 2.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 3.A leapfrog list starts 2, 5 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): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
- 5.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 6.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?
- 7.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 8.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 9.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 10.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 11.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 12.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 13.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 14.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 15.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 17.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?
- 18.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?
- 19.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 20.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?
- 21.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 22.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 23.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
- 24.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?
- 25.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 26.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 27.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
- 28.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?
- 29.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 30.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 31.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 32.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 34.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 35.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 36.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 37.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
- 39.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?
- 40.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
Answer key
- 704
- 649
- 550
- 858
- 902
- 528
- 143
- 429
- 770
- 231
- 253
- 473
- 1232
- 627
- 781
- 1056
- 550
- 374
- 374
- 429
- 418
- 748
- 814
- 396
- 407
- 286
- 715
- 506
- 913
- 847
- 693
- 979
- 968
- 396
- 880
- 319
- 473
- 1122
- 1144
- 231
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