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): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
- 2.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?
- 3.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
- 4.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?
- 5.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 6.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
- 7.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
- 8.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?
- 9.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?
- 10.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?
- 11.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
- 12.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
- 13.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?
- 14.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
- 15.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?
- 16.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 17.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
- 18.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?
- 19.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?
- 20.A leapfrog list starts 1, 2 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): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
- 22.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?
- 23.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
- 24.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
- 25.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
- 26.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
- 27.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
- 28.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 29.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?
- 30.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
- 31.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
- 32.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 33.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
- 34.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
- 35.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
- 36.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
- 37.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
- 38.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
- 39.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?
- 40.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
Answer key
- 781
- 1023
- 1001
- 605
- 253
- 682
- 814
- 627
- 847
- 880
- 748
- 726
- 979
- 1144
- 638
- 792
- 759
- 396
- 759
- 231
- 407
- 374
- 671
- 946
- 374
- 847
- 308
- 528
- 462
- 506
- 561
- 693
- 935
- 660
- 715
- 616
- 539
- 957
- 1034
- 792
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