问题
填空题
完成下列算式。
1. three + nine = ____________
2. ____________ + ten = sixteen
3. twenty － ____________ = eighteen
4. four + thirteen = ____________
5. eight + ____________ = nineteen
6. ten + seven = ____________
答案
1. twelve 2. six 3. two 4. seventeen 5. eleven 6. seventeen