This Application Problem is a part of the Lesson 13, Unit 2, Grade 1. Ten snowflakes fell on Sam's mitten, and 6 fell on his coat. Nine of the snowflakes on Sam's mitten melted. How many snowflakes are left? Write a subtraction sentence to show how many snowflakes are left. This problem continues the work started in Lesson 12, asking students to subtract 9 from 10.