Math Grade 1 Quiz Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used- 1.NBT.C.5

In this standard, students are introduced to the concept of mentally calculating 10 more or 10 less than a given two-digit number without relying on traditional counting methods. This skill hinges on the understanding of place value, where adding or subtracting 10 affects the tens place of the number. By grasping this, students can swiftly determine results without having to count each number sequentially. Furthermore, the students are expected to explain their reasoning, which aids in deepening their conceptual understanding.