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): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
- 2.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?
- 3.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
- 4.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?
- 5.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?
- 6.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 8.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?
- 9.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
- 10.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 11.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?
- 12.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?
- 13.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 14.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 15.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 16.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 17.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 18.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 19.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?
- 20.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 21.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 22.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 23.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?
- 24.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?
- 25.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?
- 26.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 27.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?
- 28.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?
- 29.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?
- 30.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
- 31.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?
- 32.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 34.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 35.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 37.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
- 38.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 39.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?
- 40.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
Answer key
- 737
- 671
- 1199
- 561
- 198
- 1232
- 649
- 1111
- 627
- 902
- 1122
- 957
- 748
- 418
- 671
- 517
- 957
- 561
- 583
- 308
- 451
- 759
- 1012
- 616
- 715
- 847
- 253
- 902
- 759
- 407
- 792
- 308
- 572
- 704
- 627
- 429
- 286
- 396
- 1001
- 198
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