I am currently solving one classification problem in which I have created a simple logistic regression model using an only single variable in each coefficient value of the variable is something else then when I have used the variable to make a multivariable model.

mod1=glm(factor(Crop_Damage)~Number_Weeks_Used,family = binomial,data = train_new[,-1])

summary(mod1)

```
Call:
glm(formula = factor(Crop_Damage) ~ Number_Weeks_Used, family = binomial, data = train_new[, -1])
Deviance Residuals:
Min 1Q Median 3Q Max
-1.1218 -0.6293 -0.4962 -0.3982 2.5507
Coefficients:
Estimate Std. Error z value Pr(>|z|)
(Intercept) -3.2135890 0.0278877 -115.23 <2e-16 ***
Number_Weeks_Used **0.0513552** 0.0007927 64.79 <2e-16 ***
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
(Dispersion parameter for binomial family taken to be 1)
Null deviance: 79458 on 88857 degrees of freedom
Residual deviance: 74993 on 88856 degrees of freedom
AIC: 74997
Number of Fisher Scoring iterations: 4
```

Using all the variable

```
mod=glm(factor(Crop_Damage)~.,family = binomial,data = train_new[,-1])
summary(mod)
Call:
glm(formula = factor(Crop_Damage) ~ ., family = binomial, data = train_new[,
-1])
Deviance Residuals:
Min 1Q Median 3Q Max
-1.6140 -0.6042 -0.4605 -0.3572 2.7729
Coefficients:
Estimate Std. Error z value Pr(>|z|)
(Intercept) -4.024e+00 7.966e-02 -50.512 < 2e-16 ***
Estimated_Insects_Count 6.492e-04 1.594e-05 40.732 < 2e-16 ***
Crop_Type -4.536e-01 2.356e-02 -19.252 < 2e-16 ***
Soil_Type -1.456e-01 1.970e-02 -7.391 1.46e-13 ***
Pesticide_Use_Category 7.135e-01 2.513e-02 28.395 < 2e-16 ***
Number_Doses_Week -7.050e-03 7.147e-04 -9.864 < 2e-16 ***
Number_Weeks_Used 1.258e-02 1.162e-03 10.828 < 2e-16 ***
Number_Weeks_Quit -2.601e-02 1.634e-03 -15.922 < 2e-16 ***
Season -5.752e-03 1.357e-02 -0.424 0.672
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
(Dispersion parameter for binomial family taken to be 1)
Null deviance: 79458 on 88857 degrees of freedom
Residual deviance: 72035 on 88849 degrees of freedom
AIC: 72053
```

I want to know the reason why this happening