====== Practice 1 ======
This practice is for big quiz 1.  The set of questions below is not an example of a quiz for 1 hour.  There will be only 3-4 questions on the quiz. 

แบบฝึกหัดด้านล่างมีไว้สำหรับเตรียมพร้อมสำหรับ big quiz 1.  อย่างไรก็ตาม จำนวนข้อในแบบฝึกหัดมีมากกว่าที่จะทำได้ใน 1 ชั่วโมง.  ใน quiz น่าจะมีประมาณ 3-4 ข้อ.

  - Find a DFA for the language { //w// | //w// contains at least two 0's and at most one 1 }. (1.6j)
  - Find a DFA for the language { //w// | //w// doesn't contain the substring 110 }. (1.6f)
  - Find a DFA for the language { //w// | //w// is a //binary// number divisible by 5 }
  - Do exercise 1.16. 
  - Convert the regular expression (0 ∪ 1)<sup>*</sup>000(0 ∪ 1)<sup>*</sup> to an NFA. (1.18)
  - Prove that every NFA can be converted to an equivalent one that has a single accept state. (1.11)
  - Given DFA's //M//<sub>1</sub>=(//Q//,Σ,δ<sub>1</sub>,//q//<sub>0</sub>,//F//) and //M//<sub>2</sub>=(//R//,Σ,δ<sub>2</sub>,//r//<sub>0</sub>,//G//) that recognize regular languages //A//<sub>1</sub> and //A//<sub>2</sub>, respectively, construct a DFA //D// that recognizes  //A//<sub>1</sub> - //A//<sub>2</sub>.