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    • ▾2nd grade
      • ▸Add and subtract within 20
        • •Add to count rectangular arrays
        • •Mentally add and subtract within 20
      • ▸Place value
        • •Place value with hundreds
        • •Convert between various representations, numbers within 1000
        • •Counting and skip-counting within 1000
        • •Intro to even and odd
        • •Compare three-digit numbers
      • ▸Add and subtract within 100
        • •Mentally add and subtract within 100
        • •Add and subtract within 100, abstract
        • •One-step word problems, add and subtract within 100
        • •Two-step word problems, add and subtract within 100
      • ▾Add and subtract within 1,000
        • •Add and subtract within 1,000
        • •Add multiple two-digit numbers
        • •Mentally add or subtract powers of ten
      • ▸Money and time
        • •Money word problems, including dollars
        • •Tell and write time, five minute increments
      • ▸Measurement
        • •Compare lengths by measuring
        • •Estimate lengths
        • •Add and subtract within 100 to solve word problems involving lengths
        • •Add and subtract within 100 on the number line
      • ▸Data
        • •Plot measurements on a line plot
        • •Draw picture and bar graphs
      • ▸Geometry
        • •Partition rectangles into rows and columns
        • •Area of a rectangle by counting unit squares
        • •Partition circles and rectangles into equal shares
        • •Draw shapes with certain attributes
        • •Intro to tessellations
     › 2nd grade › Add and subtract within 1,000

    Mentally add or subtract powers of ten

    Mentally add and subtract 10 or 100 to a given number. Mentally add or subtract with up to one exchange. For example, mentally add 80 to 192. Think 8 + 19 = 27, so the answer is 272.

    Conclude by leading this investigation:

    Rock Monster
    by MathPickle

    2.NBT.B.8: Mentally add 10 or 100 to a given number 100-900, and mentally subtract 10 or 100 from a given number 100-900.

    Lessons and practice problems