小数位值

运用位值理解，将小数四舍五入到任意位；将任意整数四舍五入到所需的精确度。

Round decimals to any place using place-value understanding; round any whole number to a required degree of accuracy

学习证据 / Evidence

• 将3.4567四舍五入到两位小数（3.46）
• 将7,654,321四舍五入到最近的100,000（7,700,000）
• 用四舍五入估算4.83 × 2.17 ≈ 5 × 2 = 10

• Round 3.4567 to 2 decimal places (3.46)
• Round 7,654,321 to the nearest 100,000 (7,700,000)
• Use rounding to estimate 4.83 × 2.17 ≈ 5 × 2 = 10

评估问题 / Assessment

{{name}}能否将3.748这样的小数四舍五入到一位小数（3.7）或两位小数（3.75），并说明他们看哪一位数字来做判断？

Can {{name}} round a decimal like 3.748 to one decimal place (3.7) or two decimal places (3.75) — and explain which digit they look at to decide?