1选择题
Look at the picture. The pencil is about 15 ________ long.
- A. millimetres
- B. centimetres
- C. metres
- D. kilometres
答案：B
解析：本题考查长度单位的选择。铅笔的长度通常用厘米（centimetres）来衡量，毫米（millimetres）太小，米（metres）和千米（kilometres）太大，不符合常识。易错点是混淆毫米和厘米的适用范围。
2选择题
There are 3,500 students in our school. 1,200 of them are boys. How many girls are there?
- A. 2,300
- B. 2,200
- C. 2,400
- D. 2,500
答案：A
解析：本题考查万以内的减法。总人数3,500减去男生人数1,200，得到女生人数2,300。计算时需注意对齐数位，从个位减起。易错点是计算过程中可能出现退位错误。
3选择题
Tom has 8 apples. Mary has 4 times as many apples as Tom. How many apples does Mary have?
答案：C
解析：本题考查“倍的认识”和多位数乘一位数。Mary的苹果是Tom的4倍，即8 × 4 = 32个。计算时注意进位。易错点是误将“4倍”理解为“多4倍”而选择A。
4选择题
A rectangle has a length of 9 cm and a width of 5 cm. What is its perimeter?
- A. 14 cm
- B. 18 cm
- C. 28 cm
- D. 45 cm
答案：C
解析：本题考查长方形周长的计算。周长 = (长 + 宽) × 2 = (9 + 5) × 2 = 14 × 2 = 28 cm。易错点是忘记乘以2，或者将周长公式与面积公式混淆。
5填空题
1 kilometre = ________ metres. 1 ton = ________ kilograms.
答案：1000; 1000
解析：本题考查长度和质量单位的换算。1千米等于1000米，1吨等于1000千克。这是基本的单位进率，需要牢记。易错点是记错进率或混淆不同单位间的换算关系。
6填空题
Calculate: 2,345 + 4,567 = ________. 8,000 - 3,654 = ________.
答案：6912; 4346
解析：本题考查万以内的加法和减法（二）。加法计算时注意进位，减法计算时注意退位。易错点是进位或退位时忘记加1或退1点，导致结果错误。
7解答题
A shop sells a toy car for 125 yuan. The price of a doll is 3 times that of the toy car. How much is the doll? Please show your work.
答案：125 × 3 = 375 (yuan)
The doll is 375 yuan.
解析：本题考查“倍的认识”和多位数乘一位数的应用。先理解“3倍”的含义，即用玩具车的价格乘以3。计算125 × 3时，注意从个位乘起，个位5×3=15，写5进1；十位2×3=6，加进位1得7；百位1×3=3，结果为375。易错点是计算过程中忘记加进位。
8解答题
Look at the fraction picture. (Imagine a circle divided into 8 equal parts, with 3 parts shaded.) What fraction of the circle is shaded? What fraction is not shaded?
答案：The shaded part is 3/8 of the circle.
The part that is not shaded is 5/8 of the circle. (Because 8/8 - 3/8 = 5/8)
解析：本题考查分数的初步认识。将一个整体（圆）平均分成8份，取其中的3份，就是八分之三（3/8）。未涂色的部分就是剩下的5份，即八分之五（5/8）。易错点是混淆分子和分母，或者误将未涂色部分也写成3/8。