In the expression 30+40+70 jillian added 30and40and then 70 while samuel added 30 and 70 and then 40 who is correct

First let's find the result of the sum:
 30 + 40 + 70 = 140
 Now let's review the operations of each one:
 Jillian added 30and40and then 70:
 30 + 40 = 70
 70 + 70 = 140
 Samuel added 30 and 70 and then 40
 30 + 70 = 100
 100 + 40 = 140
 answer
 both are correct.
 Conclusion: the order of the factors does not alter the product.