解题---**Question Section:** **Question Number:** 10 **Title:** 优选好题 **Question Stem:** 乐乐一家四口人，分别是爸爸、妈妈、乐乐和弟弟，已知4年前全家人的年龄和是58岁，而现在是73岁。请问：弟弟今年多少岁？ **Handwritten Calculations:** 73-58=15(岁) 4x4=16(岁) 16-15=1(岁) 4-1=3(岁) **Other Relevant Text:** [QR code icon] 扫一扫，看视频讲解 [QR code icon] 扫一扫，看视频讲解 **Page Number:** 23 **Image Description:** The image shows a page from a book, likely a math textbook or workbook. It contains a word problem about family ages (Question 10). To the left of the text, there is a small cartoon illustration showing three children standing and looking. Below the main question text and the handwritten calculations, there is a page number "23" inside a yellow circle. There are also two QR codes with text below them indicating they link to video explanations. The handwritten calculations are written on the page below the question stem, showing steps to solve the problem.