Need a quick 10 more & 10 less center or activity? This no prep first grade math freebie is a great way to practice mental math, place value, and the base ten system. Math skills covered:• Mentally adding 10 • Mentally subtracting 10 • Base ten number sense • Place value Supreme flexibility:These free math worksheets are flexible for many uses, including classwork, homework, assessments, fast finisher activities, place value centers, morning work, homeschool, intervention, sub plans, and much