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
- 1.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
- 2.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
- 3.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?
- 4.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?
- 5.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 6.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?
- 7.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 8.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
- 9.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?
- 10.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 11.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
- 12.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?
- 13.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 15.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
- 16.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?
- 17.A leapfrog list starts 7, 2 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): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
- 19.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?
- 20.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 21.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?
- 22.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
- 23.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
- 24.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
- 25.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 26.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
- 27.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?
- 28.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
- 29.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 30.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 31.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?
- 32.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
- 33.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 34.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?
- 35.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?
- 36.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.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?
- 38.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 39.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 40.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?
Answer key
- 627
- 1089
- 253
- 759
- 253
- 308
- 715
- 1001
- 957
- 847
- 671
- 462
- 880
- 308
- 550
- 759
- 561
- 561
- 583
- 484
- 968
- 649
- 429
- 495
- 583
- 396
- 1199
- 638
- 341
- 1001
- 396
- 429
- 583
- 968
- 847
- 803
- 528
- 759
- 660
- 759
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