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): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
- 2.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 3.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
- 4.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 5.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
- 6.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
- 7.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 8.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?
- 9.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 10.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?
- 11.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
- 12.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
- 13.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 14.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 15.A leapfrog list starts 9, 5 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 5, 4 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 9, 8 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, 1 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): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
- 20.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
- 21.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?
- 22.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 23.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?
- 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?
- 25.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
- 26.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
- 27.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?
- 28.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?
- 29.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 30.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 31.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?
- 32.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 33.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 34.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?
- 35.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 36.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?
- 37.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 38.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 39.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?
- 40.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
Answer key
- 451
- 649
- 924
- 253
- 913
- 396
- 506
- 583
- 836
- 836
- 374
- 253
- 1012
- 803
- 935
- 627
- 1199
- 418
- 968
- 660
- 1012
- 473
- 847
- 418
- 770
- 781
- 924
- 583
- 143
- 946
- 759
- 902
- 583
- 1177
- 418
- 341
- 1144
- 715
- 671
- 715
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