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.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?
- 2.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 3.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 4.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?
- 5.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 6.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?
- 7.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?
- 8.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?
- 9.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 10.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?
- 11.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 12.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 13.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?
- 14.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
- 15.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
- 16.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?
- 17.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 18.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?
- 19.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 20.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
- 21.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 22.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 23.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?
- 24.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 25.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 26.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
- 27.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?
- 28.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?
- 29.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
- 30.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?
- 31.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
- 32.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 33.A leapfrog list starts 7, 9 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 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 35.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 36.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
- 37.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 38.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?
- 39.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
- 40.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
Answer key
- 770
- 638
- 836
- 473
- 671
- 286
- 1111
- 759
- 1012
- 792
- 781
- 1001
- 671
- 913
- 979
- 1122
- 671
- 759
- 1034
- 682
- 253
- 638
- 231
- 660
- 594
- 363
- 616
- 1199
- 979
- 451
- 847
- 451
- 1177
- 748
- 715
- 1023
- 814
- 847
- 528
- 682
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