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): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
- 2.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?
- 3.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?
- 4.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?
- 5.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 6.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 7.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
- 8.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 9.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 10.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
- 11.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
- 12.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?
- 13.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 14.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?
- 15.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 16.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?
- 17.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?
- 18.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?
- 19.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
- 20.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 21.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 22.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
- 23.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 24.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?
- 25.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 26.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
- 27.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?
- 28.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 30.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 31.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 32.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 33.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
- 34.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?
- 35.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?
- 36.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?
- 37.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 39.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
- 40.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
Answer key
- 957
- 583
- 957
- 693
- 341
- 649
- 968
- 550
- 891
- 1034
- 495
- 407
- 924
- 671
- 1001
- 671
- 616
- 770
- 451
- 825
- 1012
- 847
- 726
- 968
- 363
- 484
- 781
- 682
- 682
- 781
- 814
- 836
- 704
- 770
- 913
- 572
- 550
- 847
- 1122
- 1287
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