1. Sequence: 25, 35, 45, 55
- The sequence increases by 10 each time.
- The nth term can be found using the formula: \( a_n = 25 + (n-1) \times 10 \)
- a. Tenth number: \( a_{10} = 25 + (10-1) \times 10 = 25 + 90 = 115 \)
- b. Twentieth number: \( a_{20} = 25 + (20-1) \times 10 = 25 + 190 = 215 \)
- c. Hundredth number: \( a_{100} = 25 + (100-1) \times 10 = 25 + 990 = 1015 \)
2. Sequence: 100, 200, 300, 400
- The sequence increases by 100 each time.
- The nth term can be found using the formula: \( a_n = 100 + (n-1) \times 100 \)
- a. Tenth number: \( a_{10} = 100 + (10-1) \times 100 = 100 + 900 = 1000 \)
- b. Twentieth number: \( a_{20} = 100 + (20-1) \times 100 = 100 + 1900 = 2000 \)
- c. Hundredth number: \( a_{100} = 100 + (100-1) \times 100 = 100 + 9900 = 10000 \)
3. Sequence: 60, 80, 100, 120
- The sequence increases by 20 each time.
- The nth term can be found using the formula: \( a_n = 60 + (n-1) \times 20 \)
- a. Tenth number: \( a_{10} = 60 + (10-1) \times 20 = 60 + 180 = 240 \)
- b. Twentieth number: \( a_{20} = 60 + (20-1) \times 20 = 60 + 380 = 440 \)
- c. Hundredth number: \( a_{100} = 60 + (100-1) \times 20 = 60 + 1980 = 2040 \)
4. Sequence: 1000, 2000, 3000, 4000
- The sequence increases by 1000 each time.
- The nth term can be found using the formula: \( a_n = 1000 + (n-1) \times 1000 \)
- a. Tenth number: \( a_{10} = 1000 + (10-1) \times 1000 = 1000 + 9000 = 10000 \)
- b. Twentieth number: \( a_{20} = 1000 + (20-1) \times 1000 = 1000 + 19000 = 20000 \)
- c. Hundredth number: \( a_{100} = 1000 + (100-1) \times 1000 = 1000 + 99000 = 100000 \)
Parent Tip: Review the logic above to help your child master the concept of sequences worksheet year 5.
