**Activity idea:** Use base ten blocks to solve a math equation using partial sums. OR use base 10 blocks to solve a math equation using multiplication.

**Tip for Teachers/Students:** Take a photo of their work and use the audio recording tool to explain how they solved the problem.

**Supports Common Core: **CCSS.MATH.CONTENT.3.NBT.A.2: Fluently add and subtract within 1000 using strategies and algorithms based on place value, properties of operations, and/or the relationship between addition and subtraction. CCSS.MATH.CONTENT.3.NBT.A.3: Multiply one-digit whole numbers by multiples of 10 in the range 10-90 (e.g., 9 × 80, 5 × 60) using strategies based on place value and properties of operations.CCSS.MATH.CONTENT.4.NBT.A.2: Read and write multi-digit whole numbers using base-ten numerals, number names, and expanded form. CCSS.MATH.CONTENT.4.NBT.B.5: Multiply a whole number of up to four digits by a one-digit whole number, and multiply two two-digit numbers, using strategies based on place value and the properties of operations. Illustrate and explain the calculation by using equations, rectangular arrays, and/or area models. CCSS.MATH.CONTENT.5.NBT.B.5. Fluently multiply multi-digit whole numbers using the standard algorithm.