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): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
- 2.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?
- 3.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 4.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?
- 5.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 6.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 8.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 9.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?
- 10.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?
- 11.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 12.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
- 13.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 14.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.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?
- 16.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
- 17.A leapfrog list starts 8, 6 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): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
- 19.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?
- 20.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 21.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?
- 22.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
- 23.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
- 24.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 25.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
- 26.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
- 27.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 28.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?
- 29.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 30.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 31.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
- 32.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?
- 33.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?
- 34.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
- 35.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 36.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?
- 37.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 38.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?
- 39.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
- 40.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?
Answer key
- 550
- 396
- 660
- 924
- 561
- 781
- 451
- 517
- 539
- 583
- 748
- 583
- 583
- 847
- 759
- 1144
- 968
- 594
- 902
- 957
- 198
- 231
- 539
- 726
- 693
- 506
- 649
- 561
- 781
- 759
- 1111
- 715
- 957
- 1122
- 462
- 1012
- 671
- 759
- 616
- 418
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