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
- 1.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 2.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?
- 3.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 4.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
- 5.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
- 6.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
- 8.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?
- 9.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?
- 10.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?
- 11.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 12.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
- 13.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
- 14.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?
- 15.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?
- 16.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 17.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 18.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
- 19.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?
- 20.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
- 21.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
- 22.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 23.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 24.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
- 25.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?
- 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?
- 27.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 28.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
- 29.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 30.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 31.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?
- 32.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
- 33.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?
- 34.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
- 35.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
- 36.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?
- 37.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?
- 38.A leapfrog list starts 3, 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.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?
Answer key
- 374
- 968
- 935
- 341
- 891
- 1023
- 891
- 407
- 198
- 781
- 605
- 1012
- 880
- 847
- 451
- 396
- 660
- 308
- 341
- 836
- 462
- 1089
- 847
- 803
- 726
- 671
- 473
- 759
- 561
- 594
- 627
- 363
- 550
- 748
- 605
- 781
- 495
- 869
- 616
- 583
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