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
- 1.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 2.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?
- 3.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
- 4.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 5.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?
- 6.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
- 7.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 8.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 9.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 10.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?
- 11.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?
- 12.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 13.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 14.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 16.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?
- 17.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 18.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?
- 19.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 20.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 21.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
- 22.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?
- 23.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?
- 24.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?
- 25.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?
- 26.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
- 27.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?
- 28.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?
- 29.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 30.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 31.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
- 32.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
- 33.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?
- 34.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?
- 35.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?
- 36.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.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?
- 38.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 39.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 40.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
Answer key
- 902
- 759
- 825
- 1122
- 1111
- 1122
- 1111
- 616
- 693
- 781
- 396
- 1012
- 671
- 231
- 319
- 451
- 1034
- 1012
- 682
- 847
- 770
- 946
- 253
- 957
- 803
- 1199
- 792
- 572
- 759
- 836
- 924
- 968
- 484
- 759
- 704
- 924
- 902
- 561
- 737
- 1056
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