He owes many expiations for breaking oaths (kafaarat yameen), and he does not know how to do it
Question

                I owe many expiations for breaking oaths, but when I wanted to offer this expiation, I did not know how to do it. There are no poor or needy people. Is it permissible for me to offer this expiation in the form of cash? How much should I give to each poor person? Is it permissible for me to give it to charities supporting the mujaahideen?.
Praise be to Allah.
      Firstly: 

    Kafaarat yameen (expiation for breaking an oath) means 
    freeing a believing slave, or feeding or clothing ten poor people. Whoever 
    cannot do that must fast for three days. The basis for that is the verse in 
    which Allaah says (interpretation of the meaning): 

    “Allaah will not punish you for what is unintentional in 
    your oaths, but He will punish you for your deliberate oaths; for its 
    expiation (a deliberate oath) feed ten Masaakeen (poor persons), on a scale 
    of the average of that with which you feed your own families, or clothe them 
    or manumit a slave. But whosoever cannot afford (that), then he should fast 
    for three days. That is the expiation for the oaths when you have sworn”

    [al-Maa’idah 5:89]

    Secondly: 
If a person 
    swears many oaths before breaking the oath, and the thing sworn about was 
    the same, then he only has to offer expiation once. But if he swore many 
    oaths about different things, then he has to offer expiation for each oath. 

    Thirdly: 

    Kafaarat al-yameen must be given to the poor, as stated by 
    Allaah. There is no reason why it cannot be given to the mujaahideen who are 
    fighting for the sake of Allaah, because Allaah has mentioned them among 
    those who may be given zakaah, especially if there are no poor or needy 
    people to whom it may be given. 

    Fourthly: 

    It is not permissible to pay cash instead of offering 
    kafaarat al-yameen, because that is going against the text. Your Lord is not 
    forgetful and He did not state that cash may be given instead of the 
    expiations mentioned in the text.