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
- 1.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 2.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 3.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?
- 4.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
- 5.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 6.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?
- 7.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
- 8.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 10.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?
- 11.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?
- 12.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 13.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 14.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
- 15.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
- 16.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 17.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 18.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?
- 19.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
- 20.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 21.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 22.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 23.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 24.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. 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?
- 26.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 27.A leapfrog list starts 6, 6 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 3, 6 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, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
- 30.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 31.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?
- 32.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?
- 33.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 34.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
- 35.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?
- 36.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 37.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?
- 38.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 39.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 40.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
Answer key
- 341
- 583
- 759
- 858
- 726
- 924
- 638
- 517
- 660
- 770
- 957
- 682
- 286
- 1067
- 341
- 308
- 935
- 759
- 484
- 704
- 594
- 946
- 1111
- 418
- 803
- 660
- 858
- 693
- 583
- 957
- 253
- 671
- 748
- 1056
- 308
- 1012
- 946
- 528
- 770
- 319
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