BMR 计算器 React Native

如何解决BMR 计算器 React Native

    import React,{ Component,useState } from "react";
    
    export class Register extends Component {
      constructor(props) {
        super(props);
    
        this.state = {
          In: "",lbs: "",age: "",gender: "",};
      }
    
    render() {
    
        //BMR Calculator
        const { In } = this.state;
        const { lbs } = this.state;
        const { age } = this.state;
        const { gender } = this.state;
    
    return (
          <SafeAreaView>
                <View>
                  <TextInput
                    label="username"
                    onChangeText={(name) => this.setState({ name })}
                  />
    
                  <TextInput
                    label="email"
                    onChangeText={(email) => this.setState({ email })}
                  />
    
                  <TextInput                    
                    label="password"
                    onChangeText={(password) => this.setState({ password })}
                  />
                </View>
  
                    <Text>Weight</Text>

                      <TextInput
                        placeholder="In"
                        keyboardType="numeric"
                        maxLength="2"
                        onChangeText={(In) => this.setState({ In })}
                        style={styles.heightImperialIn}
                      />

                   <Text>Weight</Text>

                     <TextInput
                      placeholder="lbs"
                      keyboardType="numeric"
                      maxLength="3"
                      value={lbs}
                      onChangeText={(lbs) => this.setState(+e.target.value)}
                      //onChangeText={(lbs) => this.setState({ lbs })}
                      style={styles.weigthImperial}
                     />

                   <Text style={styles.txtAge}>Age</Text>

                    <TextInput
                      placeholder="18"
                      keyboardType="numeric"
                      maxLength="2"
                      value={age}
                      onChange={(age) => this.setState(+e.target.value)}
                      //onChangeText={(age) => this.setState({ age })}
                      style={styles.ageImperial}
                    />

                   <Text>Gender</Text>

                    <View style={{ top: hp("10%") }}>
                      <RNPickerSelect
                        style={pickerStyle}
                        placeholder={{
                          label: "Select a gender",value: null,}}
                        onValueChange={(gender) => this.setState({ gender })}
                        items={[
                          { label: "Male",value: "male" },{ label: "Female",value: "female" },]}
                      />
                    </View>
             </SafeAreaView>

大家好，我有 BMR 计算器的这两个方程：

1. 男性=66+(6.2lbs)+(12.7In)-(6.76*age)
2. female=655.1+(4.35lbs)+(4.7In)-(4.7*age)

我的问题是如何根据性别从上面的文本输入中获取 lbs、In 和 age 的值并将它们插入到两个等式之一中由用户选择，并显示结果？

谢谢