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
- 1.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 2.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?
- 3.A leapfrog list starts 5, 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.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?
- 6.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 8.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 9.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?
- 10.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 11.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 12.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?
- 13.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 14.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?
- 15.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 16.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 17.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 18.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?
- 19.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?
- 20.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 21.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 22.A leapfrog list starts 9, 1 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, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 24.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 25.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 26.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?
- 27.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?
- 28.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?
- 29.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?
- 30.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 31.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
- 32.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?
- 33.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?
- 34.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 35.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 36.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
- 37.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 38.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?
- 39.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 40.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
Answer key
- 946
- 407
- 539
- 286
- 1199
- 836
- 671
- 550
- 1012
- 770
- 308
- 957
- 1111
- 418
- 814
- 572
- 418
- 319
- 198
- 451
- 583
- 583
- 781
- 374
- 1023
- 671
- 231
- 143
- 770
- 473
- 407
- 319
- 1067
- 583
- 1012
- 319
- 594
- 704
- 539
- 572
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