The Standard Multiplication Algorithm
with a TwoDigit Multiplier
You have learned to calculate
multiplications such as 67 × 54 in parts. In the usual, traditional way of multiplying
there are also three separate calculations. 



Study these examples, too. Note the extra zero needed in the ones place on the second line! 



1. Fill in the missing digits and complete the calculations.
a.  b.  c.  d. 
2. Multiply.
a. 
b. 
c. 
d. 
3. Multiply. But first, estimate the result! Compare your final answer to
your estimation. If there is a big
difference, you might have an error somewhere.
a. Estimate: ______ × ______
= __________

b. Estimate: ______ × ______
= __________

c. Estimate: ______ × ______
= __________

5. Solve the word problems. Write a number sentence for each one.
a. How many eggs are in 15 dozen?
___________________________________ Estimate: ___________________________

b. How many minutes are
there in 21 hours?
___________________________________ Estimate: ___________________________

c. The 455 pupils in a school are going to a zoo by bus. One bus can seat 39 passengers. Are 11 buses enough to take them all? ___________________________________ Estimate: ___________________________

d. Each month, Brenda earns $21 from watering the neighbor's flowers. How much does she earn in a year? ___________________________________ Estimate: ___________________________

6. Multiply. Estimate the answer on the line.
a.
51 × 19 ≈_________

b. 45 × 28 ≈_________ 
c. 12 × 18 ≈_________

d. 84 × 95 ≈_________

7. Solve. Estimate before you calculate.
a. Find the change, if a teacher buys
15 shirts
Estimation: 


b. One year has 52 weeks. Sally pays $98 weekly in rent. How much will she pay in a year?
Estimation: 
8. Calculate in the correct order.
a. 60 × (10 + 20) × 2 = _________ 30 × (40 – 40) × 2 = _________ 
b. 8 × (200 – 100) – 500 = _________ (800 – 200) × 20 + 100 = _________ 
Fill in the missing numbers in these multiplications:

This lesson is taken from Maria Miller's book Math Mammoth Multiplication 2, and posted at www.HomeschoolMath.net with permission from the author. Copyright © Maria Miller.
Math Mammoth Multiplication 2
A selfteaching worktext for 4th grade that covers multiplying by whole tens and hundreds, multidigit multiplication in columns, order of operations, word problems, scales problems, and money problems.
Download ($5.10). Also available as a printed copy.