Let’s solve each row step by step. We’ll calculate:
-
10% of the bill → just move decimal one place left (or multiply by 0.1)
-
5% (sales tax) → half of 10%
-
15% → 10% + 5%
-
20% → double the 10%
We’ll do this for each bill amount.
---
Row 1: Bill = $12.20
- 10% = $12.20 × 0.1 =
$1.22
- 5% = half of $1.22 =
$0.61
- 15% = $1.22 + $0.61 =
$1.83
- 20% = $1.22 × 2 =
$2.44
---
Row 2: Bill = $18.30
- 10% = $18.30 × 0.1 =
$1.83
- 5% = half of $1.83 =
$0.915 → round to nearest cent =
$0.92
- 15% = $1.83 + $0.92 =
$2.75
- 20% = $1.83 × 2 =
$3.66
*(Note: In real life, we usually round money to the nearest cent. So $0.915 becomes $0.92)*
---
Row 3: Bill = $80.00
- 10% = $80.00 × 0.1 =
$8.00
- 5% = half of $8.00 =
$4.00
- 15% = $8.00 + $4.00 =
$12.00
- 20% = $8.00 × 2 =
$16.00
---
Row 4: Bill = $5.75
- 10% = $5.75 × 0.1 =
$0.575 → round to
$0.58
- 5% = half of $0.58 =
$0.29
- 15% = $0.58 + $0.29 =
$0.87
- 20% = $0.58 × 2 =
$1.16
*(Again, rounding $0.575 up to $0.58 because it’s halfway — standard rule is to round up at .5)*
---
Row 5: Bill = $6.99
- 10% = $6.99 × 0.1 =
$0.699 → round to
$0.70
- 5% = half of $0.70 =
$0.35
- 15% = $0.70 + $0.35 =
$1.05
- 20% = $0.70 × 2 =
$1.40
---
Row 6: Bill = $2.90
- 10% = $2.90 × 0.1 =
$0.29
- 5% = half of $0.29 =
$0.145 → round to
$0.15
- 15% = $0.29 + $0.15 =
$0.44
- 20% = $0.29 × 2 =
$0.58
---
Row 7: Bill = $66.25
- 10% = $66.25 × 0.1 =
$6.625 → round to
$6.63
- 5% = half of $6.63 =
$3.315 → round to
$3.32
- 15% = $6.63 + $3.32 =
$9.95
- 20% = $6.63 × 2 =
$13.26
---
Row 8: Bill = $4.50
- 10% = $4.50 × 0.1 =
$0.45
- 5% = half of $0.45 =
$0.225 → round to
$0.23
- 15% = $0.45 + $0.23 =
$0.68
- 20% = $0.45 × 2 =
$0.90
---
Row 9: Bill = $74.80
- 10% = $74.80 × 0.1 =
$7.48
- 5% = half of $7.48 =
$3.74
- 15% = $7.48 + $3.74 =
$11.22
- 20% = $7.48 × 2 =
$14.96
---
Row 10: Bill = $20.25
- 10% = $20.25 × 0.1 =
$2.025 → round to
$2.03
- 5% = half of $2.03 =
$1.015 → round to
$1.02
- 15% = $2.03 + $1.02 =
$3.05
- 20% = $2.03 × 2 =
$4.06
---
Final Answer:
| # | Bill | 10% | 5% (sale tax) | 15% | 20% |
|----|----------|--------|---------------|--------|--------|
| 1 | $12.20 | $1.22 | $0.61 | $1.83 | $2.44 |
| 2 | $18.30 | $1.83 | $0.92 | $2.75 | $3.66 |
| 3 | $80.00 | $8.00 | $4.00 | $12.00 | $16.00 |
| 4 | $5.75 | $0.58 | $0.29 | $0.87 | $1.16 |
| 5 | $6.99 | $0.70 | $0.35 | $1.05 | $1.40 |
| 6 | $2.90 | $0.29 | $0.15 | $0.44 | $0.58 |
| 7 | $66.25 | $6.63 | $3.32 | $9.95 | $13.26 |
| 8 | $4.50 | $0.45 | $0.23 | $0.68 | $0.90 |
| 9 | $74.80 | $7.48 | $3.74 | $11.22 | $14.96 |
| 10 | $20.25 | $2.03 | $1.02 | $3.05 | $4.06 |
Parent Tip: Review the logic above to help your child master the concept of 7th grade math sales tax worksheet.