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 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.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?
- 3.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 4.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?
- 5.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 6.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 7.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
- 8.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 9.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
- 10.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?
- 11.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
- 12.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?
- 13.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
- 14.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 15.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 16.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?
- 17.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
- 18.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 19.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
- 20.A leapfrog list starts 3, 9 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): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
- 22.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?
- 23.A leapfrog list starts 1, 6 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 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 26.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 27.A leapfrog list starts 5, 9 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 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.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?
- 30.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?
- 31.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 32.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
- 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?
- 34.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 35.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 37.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
- 38.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
Answer key
- 363
- 572
- 671
- 231
- 726
- 341
- 792
- 594
- 1012
- 858
- 484
- 286
- 1232
- 473
- 143
- 781
- 803
- 627
- 1001
- 957
- 319
- 957
- 583
- 1177
- 253
- 583
- 1067
- 143
- 671
- 946
- 308
- 913
- 253
- 968
- 792
- 759
- 561
- 715
- 847
- 605
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