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 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 2.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 3.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?
- 4.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 5.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 6.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?
- 7.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?
- 8.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?
- 9.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
- 10.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 11.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?
- 12.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?
- 13.A leapfrog list starts 9, 3 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 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 16.A leapfrog list starts 9, 4 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): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
- 18.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 19.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 20.A leapfrog list starts 7, 5 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, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
- 22.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
- 23.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 24.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?
- 25.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 26.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 27.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?
- 28.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?
- 29.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 30.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?
- 31.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?
- 32.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?
- 33.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 34.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
- 35.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 36.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
- 37.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
- 38.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 39.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 40.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
Answer key
- 484
- 418
- 704
- 286
- 759
- 1177
- 792
- 1199
- 704
- 836
- 935
- 1056
- 759
- 671
- 308
- 847
- 869
- 649
- 1012
- 825
- 495
- 517
- 583
- 1067
- 1023
- 847
- 143
- 374
- 759
- 286
- 253
- 506
- 319
- 616
- 825
- 605
- 1232
- 781
- 946
- 374
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