IXL http://www.ixl.com/ から算数の問題を抜粋
子供の算数の問題簡単な単語ばかりですが
英語での説明の流れが非常に勉強になります。
Estimate the amount of the tip by rounding the bill to the nearest dollar before calculating.
20% tip on a bill of $28.58
The amount of the tip is approximately $（ ）.
解答は ↓
Round $28.58 to the nearest dollar.
$28.58 → $29
Find 10% of $29.
1/10 × $29＝$2.90
Now double that result. That will give you 20% of $29.
2 × $2.90 = $5.80
20% tip on a bill of $28.58 is approximately $5.80.
Compare your estimate to the exact answer:
Estimate: 20% of $28.58 ≈ 20% of $29 = $5.80
Exact answer: 20% of $28.58 = $5.716 → $5.72