Hello, Sazza!

Are you baffled by their hints?

(a) .23 × 317 .≈ .20 ×300 .= .6000

**[apply the rule, 2 × 3, then add the zeroes]** When you multiply 20 by 300, do **not** do it like this: Code:

3 0 0
2 0
--------
0 0 0
6 0 0
---------
6 0 0 0

It's correct, but some ten-year-olds will laugh at you.

The only *serious* multiplication you did was: .2 × 3 = 6

. . All the rest was "zero times something".

So the answer is: "6 and a bunch of zeros"

. . Okay, *how many* zeros?

Just count them up!

2**0** has __one__ zero, 3**00** has __two__ zeros.

. . There are __three__ zeros. .(Add them.)

The answer is: ."6 with three zeros" .= .6000

See? .You can "eyeball" the problem and get the answer.

(b) .4250 ÷ 23 .≈ .4000 ÷ 20 .= .200

**[cancel tens]**

Once again, you are __not__ expected to divide like this: Code:

2 0 0
-----------
2 0 ) 4 0 0 0
4 0
---
0 0
0 0
---

The only *real* division you did was: .4 ÷ 2 .= .2

. . All the rest was "0 divided by 20"

So the answer is: "2 and a bunch of zeros"

. . Okay, *how many* zeros?

4**000** has __three__ zeros. .2**0** has __one__ zero.

. . This time we *subtract*: .__two__ zeros.

The answer is: ."2 and two zeros" .= .200

Get the idea?