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): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
- 2.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?
- 3.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?
- 4.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 5.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 6.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 7.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?
- 8.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 10.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 11.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?
- 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.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 15.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 16.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?
- 17.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
- 18.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 19.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 21.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
- 22.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?
- 23.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
- 25.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?
- 26.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?
- 27.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 28.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 29.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?
- 30.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 31.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?
- 32.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
- 33.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 34.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 35.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?
- 36.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 37.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 38.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 39.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 40.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
Answer key
- 715
- 1012
- 605
- 847
- 715
- 946
- 869
- 473
- 572
- 671
- 1177
- 286
- 1111
- 462
- 803
- 693
- 748
- 814
- 341
- 583
- 1089
- 451
- 726
- 759
- 726
- 616
- 891
- 286
- 913
- 407
- 836
- 143
- 1023
- 583
- 231
- 561
- 319
- 836
- 968
- 781
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