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, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 3.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?
- 4.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 5.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
- 6.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 7.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 8.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
- 9.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?
- 10.A leapfrog list starts 2, 2 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 2, 8 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 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 13.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
- 14.A leapfrog list starts 6, 1 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 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 17.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?
- 18.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?
- 19.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 20.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 21.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 22.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 23.A leapfrog list starts 7, 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 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 26.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 27.A leapfrog list starts 3, 8 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 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.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?
- 30.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 31.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 32.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 33.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?
- 34.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 36.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 37.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 38.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?
- 39.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 40.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?
Answer key
- 913
- 638
- 759
- 462
- 649
- 583
- 1034
- 946
- 1232
- 286
- 814
- 770
- 726
- 418
- 1012
- 627
- 374
- 1144
- 759
- 1144
- 528
- 649
- 1177
- 1199
- 759
- 902
- 869
- 1056
- 253
- 286
- 616
- 968
- 1122
- 616
- 858
- 1199
- 1089
- 704
- 693
- 418
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