update test set num = replace([num], [num],[color=#FF0000] [num]*10[/color])

declare @test table (num numeric(5,1))
insert into @test
select 8 union all
select 7.2 union all
select 6 union all
select 21 union all
select 7 union all
select 12

update @test
set num=case when num*10>100 then 100 else num*10 end

select * from @test
/*
num
---------------------------------------
80.0
72.0
60.0
100.0
70.0
100.0
*/