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): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
- 2.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 3.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?
- 4.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
- 5.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?
- 6.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
- 7.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
- 8.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 9.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
- 10.A leapfrog list starts 1, 3 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, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
- 12.A leapfrog list starts 6, 8 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 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 14.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 15.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
- 16.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 17.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
- 18.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?
- 19.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?
- 20.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?
- 21.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
- 22.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?
- 23.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
- 24.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
- 25.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 26.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
- 27.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?
- 28.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?
- 29.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 30.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
- 31.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?
- 32.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
- 33.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
- 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 4, 6 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 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 37.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
- 38.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
- 40.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
Answer key
- 594
- 671
- 1001
- 1067
- 924
- 528
- 957
- 396
- 286
- 319
- 462
- 1034
- 1287
- 913
- 1089
- 1111
- 418
- 495
- 1089
- 935
- 825
- 594
- 704
- 594
- 583
- 1023
- 836
- 418
- 726
- 583
- 759
- 143
- 1056
- 968
- 748
- 1056
- 1287
- 649
- 583
- 1144
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