1. I can extend written methods to
multiplication of HTU x U and U.t x U

2. 258 x 9 Estimate = 258 x 10 = 2580 BUT this will be “out” by 258.
Estimates made when multiplying are often not
as close as those done when adding or subtracting.
Q. If 258 x 10 = 2580 how else could we have calculated x 9?

3. 258
x 9
1800
450 72
2322
Q. Where do you think 1800, 450, 72 and 2322 have come from?

4. 258
x 9
= x 9
450 = x 9
72 = x 9 =
It’s easy really!

5. Look at this one:
473 x 9
473
x 9
3600
630 27
4257

6. Look at this one:
473 x 9
473
x 9
3600 = x 9
630 = x 9
27 = x 9
4257 =

7. Try these.
Remember to approximate first.
254 x 6
378 x 9
254 x 5
872 x 9
746 x 6

8. LOOK… 258 x 9 18 45 72 135 Q. Can the answer possibly be right?
What is wrong?

9. Remember to use 0 as a placeholder
Here the answer Here the answer
figures are in figures are in
the wrong place. the right place.
x x 9
The PLACE VALUE of the figures is VITAL.
Remember to use 0 as a placeholder

10. 5.7 x 6
How could we lay this out vertically?

11. We need to think carefully about where the figures go ….. PLACE VALUE
5.7
x 6 30
4.2
34.2
Here we need to ALIGN the DECIMAL POINTS