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.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?
- 2.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 3.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?
- 4.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 5.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?
- 6.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 7.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 8.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
- 9.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
- 10.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?
- 11.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 12.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
- 13.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 14.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
- 15.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?
- 16.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 17.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?
- 18.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 19.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 20.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 21.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 22.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
- 23.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 24.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?
- 25.A leapfrog list starts 4, 7 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): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
- 27.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?
- 28.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 29.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?
- 30.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?
- 31.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?
- 32.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?
- 33.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?
- 34.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?
- 35.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 36.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 37.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?
- 38.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?
- 39.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?
- 40.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
Answer key
- 671
- 770
- 649
- 198
- 231
- 1012
- 572
- 671
- 792
- 979
- 1111
- 869
- 660
- 682
- 1199
- 231
- 1287
- 649
- 715
- 1067
- 935
- 836
- 451
- 143
- 836
- 1177
- 726
- 407
- 858
- 1144
- 374
- 418
- 1056
- 1177
- 473
- 583
- 396
- 913
- 891
- 671
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