This is a collection of lessons created to address the 4.NBT.4 common core standard for fourth grade. The lessons include: -Using the standard algorithm for addition -Using the standard algorithm for subtraction -How to add zeroes to number phrases that are multiples of 10 (for example: 3 tens = 30, 7 thousands = 7,000) Also included are warm-ups and cool-downs. There are 46 slides in this file, which should last you approximately one week. The practice problems at the end of each session/les