Number and Operations in Base Ten: Understanding Fractions as Equal Parts of a Whole (CCSS.3.NBT.3)
Common Core 3rd Grade Math · Learn by Concept
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Common Core 3rd Grade Math › Number and Operations in Base Ten: Understanding Fractions as Equal Parts of a Whole (CCSS.3.NBT.3)
What is $40 \times 8$?
320
32
360
3,200
Explanation
Multiply the nonzero digits: $4 \times 8 = 32$. Because 40 has one zero, attach one zero to get 320.
What is $30 \times 4$?
34
300
12
120
Explanation
Think $3 \times 4 = 12$ and then attach one zero because 30 has one zero, so $120$.
What pattern do you see when multiplying a one-digit number by a multiple of 10, like $2 \times 30$, $3 \times 40$, or $5 \times 70$?
Multiply the digits that are not zero and do not add any zeros.
Multiply the one-digit numbers and then attach one zero to the product.
Add the two numbers and then put a zero at the end.
The product gets smaller when the tens number gets larger.
Explanation
You multiply the nonzero digits and then attach one zero because a multiple of 10 has one zero.