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): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
- 2.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
- 3.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?
- 4.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
- 5.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 6.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 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?
- 8.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 9.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
- 11.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?
- 12.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 13.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?
- 14.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 15.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 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?
- 17.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 18.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 19.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?
- 20.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 21.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?
- 22.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?
- 23.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 24.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 25.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 26.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?
- 27.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 28.A leapfrog list starts 6, 9 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): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
- 30.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?
- 31.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
- 32.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?
- 33.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 34.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 35.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?
- 36.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 38.A leapfrog list starts 1, 7 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 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 40.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
Answer key
- 550
- 660
- 847
- 858
- 407
- 671
- 869
- 748
- 902
- 198
- 1144
- 1001
- 616
- 308
- 880
- 1111
- 616
- 759
- 418
- 1023
- 198
- 671
- 528
- 495
- 429
- 792
- 451
- 1122
- 847
- 1067
- 198
- 517
- 649
- 1122
- 1012
- 319
- 473
- 671
- 473
- 847
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