Students will learn how to multiply one-digit numbers by multiples of 10. The idea is to multiply two one-digit numbers, then tack on a zero. First, students will learn how to solve mathematical problems.

Multiplying by multiples of 10 by Khan Academy

Multiply by tens by Khan Academy

Next, students will learn how to solve word problems.

Multiplying by tens word problem by Khan Academy

Multiply by tens word problems by Khan Academy

Next, give your students these challenges:

- Let's Investigate Triangles by NRICH
- Domino Sorting by NRICH

A number lock has a three-digit key. Hints of these three digits are given below. Can you crack the code?

Here's the solution: From clues 1 and 2, the digit 6 can be eliminated. From clue 3, the digits 2 and 0 must be correct, but in the wrong positions. From clue 1, the digit 2 must go in the 3rd slot. From clue 3, the digit 0 must go in the 1st slot. From clue 2, 5 must be correct, but in the wrong position, so 5 goes in the only remaining slot, the 2nd one. Thus, the answer must be 052.

Conclude by leading this investigation:

Banyan Tree Root Puzzle (Addition)

by MathPickle

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.