我在使用弹性盒子布局的时候遇到一个问题，我有10个元素，想分成两行显示。但是我不想固定每个元素的宽度，我的代码如下，该如何修改呢。

<div class="mall-sell item-box">                
        <div class="mall_sell-item">
            <img src="sell_img.jpd">
            <p>Hello</p>
        </div>
        <div class="mall_sell-item">
            <img src="sell_img.jpd">
            <p>Hello</p>
        </div>    
        <div class="mall_sell-item">
            <img src="sell_img.jpd">
            <p>Hello</p>
        </div>    
        <div class="mall_sell-item">
            <img src="sell_img.jpd">
            <p>Hello</p>
        </div>    
        <div class="mall_sell-item">
            <img src="sell_img.jpd">
            <p>Hello</p>
        </div>        
        <div class="mall_sell-item">
            <img src="sell_img.jpd">
            <p>Hello</p>
        </div>    
        <div class="mall_sell-item">
            <img src="sell_img.jpd">
            <p>Hello</p>
        </div>    
        <div class="mall_sell-item">
            <img src="sell_img.jpd">
            <p>Hello</p>
        </div>    
        <div class="mall_sell-item">
            <img src="sell_img.jpd">
            <p>Hello</p>
        </div>
        <div class="mall_sell-item">
            <img src="sell_img.jpd">
            <p>Hello</p>
        </div>                                    
    </div>

css代码如下：

.mall-sell {
    width: 100%;
    overflow: hidden;
    display: flex;
    flex: 1;
    flex-wrap: wrap;    
    position: relative;
}
.mall-sell .mall_sell-item {        
    flex: 1;
    float: left;
    position: relative;
    height: 1.68rem;
    line-height: 1.68rem;
    text-align: center;
    vertical-align: middle;
    margin-top: 0.266666rem;
}
.mall-sell .mall_sell-item img {
    display: block;
    width: 1.2rem;
    height: 1.2rem;
    line-height: 0.146666rem;
    text-align: center;
    background-color: rgb(210,216,221);
}
.mall-sell .mall_sell-item p {
    float: right;
    width: 1.36rem;
    height: 0.333333rem;
    line-height: 0.333333rem;
    font-family: PingFang-SC-Regular;
    @include font-dpr(13px);
    font-size: 0.346666rem;
    text-align: center;
}

我现在是第一行显示7个，第二行显示剩余三个，不知道该怎么改。
谢谢