I don't think the education system is at fault. Mental arithmetic is a skill you need to practice, and since a lot of us either spend a lot of time at a computer or always have one in our pocket, why would we?
1. If you bought four packs of tea: chamomile ($4.60), green ($4.15), black ($3.35) and lemon ($1.80) with a $20 note, how much change would you get?
2. If a litre of cola costs $3.15, how much will you pay for a third of a litre?
3. If a football club offers the same discount for all season tickets - Main Stand - $50 for single entry, $300 for a season; Stand 2 - $35 for single entry, $210 for a season; Stand 3 - $25 for single entry, $150 for a season - what would the price be for a Stand 4 season ticket, where a single entry costs $21?
The answers are $6.10, $1.05 and $126 respectively.