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): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
- 2.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 3.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
- 4.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
- 5.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?
- 6.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?
- 7.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 8.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?
- 9.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 11.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 12.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
- 13.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 14.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?
- 15.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 16.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
- 17.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?
- 18.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?
- 19.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?
- 20.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
- 22.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?
- 23.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?
- 24.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 25.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 26.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 27.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 28.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?
- 29.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 30.A leapfrog list starts 9, 2 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): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
- 32.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?
- 33.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?
- 34.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 35.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 36.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?
- 37.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 38.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?
- 39.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?
- 40.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
Answer key
- 1177
- 957
- 693
- 1144
- 946
- 550
- 550
- 451
- 759
- 495
- 561
- 506
- 506
- 946
- 891
- 1111
- 616
- 803
- 869
- 407
- 957
- 935
- 198
- 946
- 913
- 253
- 759
- 583
- 319
- 671
- 682
- 880
- 253
- 594
- 671
- 737
- 374
- 605
- 396
- 935
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