瞧！我们向希望工程捐赠了很多学习用品，快来统计数字。1. Books: seven + fourteen = _______________
2. Pens: ten + fifteen = _______________
3. Pencils: fourteen + fifteen = _______________
4. Rulers: two + eight + eighteen = _______________
5. Pencil cases: twenty + five + _______________= twenty-nine 1. twenty-one 2. twenty-five 3. twenty-nine 4. twenty-eight 5. four