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
- 1.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 2.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
- 3.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?
- 4.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 5.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
- 6.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 7.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?
- 8.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
- 9.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 10.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 11.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 12.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
- 13.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
- 14.A leapfrog list starts 6, 3 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 2, 1 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): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
- 17.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
- 18.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
- 19.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 20.A leapfrog list starts 1, 5 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): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
- 22.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?
- 23.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
- 24.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?
- 25.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?
- 26.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?
- 27.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 28.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.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?
- 30.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?
- 31.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 32.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 33.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 34.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 35.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?
- 36.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
- 37.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?
- 38.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
- 39.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
- 40.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?
Answer key
- 583
- 759
- 462
- 1001
- 231
- 1287
- 561
- 693
- 935
- 583
- 638
- 902
- 627
- 594
- 198
- 550
- 572
- 649
- 825
- 495
- 814
- 341
- 737
- 1023
- 1089
- 583
- 715
- 979
- 759
- 616
- 462
- 957
- 286
- 946
- 660
- 517
- 231
- 253
- 473
- 726
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