Subtracting with tidy numbers

This week in math I have been learning to solve problems by equal additions that turn one of the numbers into a tidy number.

e.g-183-68=add 2 to 183 and 68 so

185-70=?

80-70=10

100+10+5=115

I am learning to figure out strategies using Tidy Numbers.
I know it very well and I’m good at it.This strategy is simple.

e.g;1894+__=2000

189(4)+6=1900 1900+100=2000
6+100=106

Measurement

This week in Room7 we are leaning about Measurement,Measurement is like Measuring a door or a pencil. For a pencil you have to Measure it with cm(centimeter) and a door may be m(meter) or cm(centimeter) and if you have to Measure St Pius to St Patrick you have to use km(kilometer).
1cm=10mm
1m=100cm
1km=1000m