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
- 1.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 2.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
- 3.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?
- 4.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
- 5.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?
- 6.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 8.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 9.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 10.A leapfrog list starts 9, 6 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 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 12.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 13.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?
- 14.A leapfrog list starts 7, 8 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 3, 8 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 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 17.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 19.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 20.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 21.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 22.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?
- 23.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 24.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
- 25.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
- 27.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 28.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
- 29.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 30.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
- 31.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
- 32.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?
- 33.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?
- 34.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 35.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?
- 36.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 37.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 38.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 39.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 40.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?
Answer key
- 198
- 583
- 572
- 319
- 528
- 946
- 429
- 286
- 792
- 1023
- 693
- 957
- 913
- 1089
- 869
- 803
- 539
- 935
- 1089
- 627
- 341
- 671
- 231
- 253
- 737
- 495
- 671
- 880
- 561
- 671
- 627
- 231
- 704
- 858
- 605
- 1287
- 913
- 803
- 583
- 1177
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